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Repair a Windows Dual-Boot

Last reviewed: April 2005

Repair a XP/2000/NT + WIN9x/Me Dual-Boot.

You should never destroy either Windows if a dual-boot fails. You can always save one Windows, and usually both (and the dual-boot).

The most common, and solvable, problems include

  • A Win9x boot option is missing from the menu (it's not in Boot.ini).
  • Win9x will not boot (missing Bootsect.dos, or Fixboot did not work).
  • NTLDR is missing or corrupt (no Boot Loader menu).
  • The XP/... boot sector must be Repaired (damaged, or Win9x was installed last)

A serious situation exists if the existing PC system partition (C:) was mistakenly converted to NTFS for a XP/... installation. This will never work when a Win9x is installed. A Win9x can never boot when the PC system partition uses NTFS.

Save this page before setting up a dual-boot.

REPAIR Win9x+XP/2K/NT DUAL-BOOT

If NTLDR is missing - there is no Boot Loader menu:
• Copy NTLDR & NTDETECT.COM from \i386\ folder on the CD to C:\. Reboot. Test.

If a Win9x/Me boot option does not appear in the Boot Loader menu:
• Use ATTRIB -R C:\BOOT.INI from a prompt. Edit C:\Boot.ini, and add this line
   C:\="Microsoft Windows 9x"
   to the [operating systems] section if C:\="..." is not there. Reboot. Test.

If Bootsect.dos is missing or corrupt:
• Read Bootsect.dos, and/or Full Repair, below.

If Windows XP/2K/NT can not boot:
• Repair the Boot Sector, see below.

If the boot paths are incorrect:   • Also read #2 Boot.ini below.
• Check has Master/Slave been switched if dual-booting two hard disks (see below).
Copy ALL boot files to C:\, or current system partition, if not there. Windows likes
   the PC system partition to be drive C:, so the drive letters may have changed.
• Advanced users: Check the boot paths in Boot.ini in relation to the Wins' installed.
   rdisk(n) where 'n' is the disk number on that channel (counting from 0)
   partition(p) where 'p' is partition number on that HD (count from 1; Primaries first)
   Reboot. Test.

If XP/2K/NT will still not boot, or the dual-boot does not work:
• Execute Full Repair, below. If that fails, then
• Restart Setup. From Recovery, choose the option to recover a destroyed system or system disk.

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BOOT SECTORS - REPAIR WINDOW XP/2K/NT

XP/2K: To Repair a damaged Windows XP or 2000 Boot Sector:
1. Make the CD-ROM, or floppy drive, the first Boot Device in the BIOS/CMOS.
2. Boot from the XP/2K CD or the installation disks.
3. At the Welcome screen, press F10.
4. Select Repair.
5. Select Console.
6. Type in - and then press [Enter]
      FIXBOOT
    Answer Y. You sometimes must specify the PC system partition (read FIXBOOT).
7. Type in Exit to exit the Console/reboot. Rectify BIOS's first Boot Device. Test.

NT: To Repair a damaged Windows NT Boot Sector:
1. Make the CD-ROM, or floppy drive, the first Boot Device in the BIOS/CMOS.
2. Boot from the NT CD or Setup Disk 1 (and then Disk 2).
3. Press any key, if asked, to boot from CD. Press [Enter] to begin.
4. Press R for Repair when the Setup options appear.
5. Select only the option "Inspect boot Sector" - deselect any other options.
6. Insert a ERD for this Windows when requested,
    or press Esc to let repair look for the repair information.
7. Reboot when finished. Rectify BIOS's first Boot Device. Test.

ERD: Emergency Repair Disk:
If you are prompted to insert a ERD made by this Windows and you do not have it, then the repair looks in Boot.ini for the boot path to the repair information on your computer. A failed repair may indicate the boot path in Boot.ini is incorrect. If necessary, edit Boot.ini correcting the boot path, or use bootcfg /rebuild to rebuild Boot.ini. Then run the repair again.

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FIXBOOT and DRIVE LETTERS

If Windows 9x will not boot even if it appears in the Boot Loader menu:

Example: To install Win9x on an NTFS Wins, we need a new C: partition (FAT/32, Active, PC system partition). We use PartitionMagic, or add a hard disk as Primary Master. When Win9x is on the new C: and FIXBOOT is run from Recovery Console via XP's CD, the XP boots from the menu but Win9x may not boot. FIXBOOT needs to be pointed to the new PC system partition (new C:).
Why?
Internally, XP may see our new C: as D: or E: or . . .. FIXBOOT needs that internal drive letter so it can fix the new PC system partition - which fortunately always contains the Win9x boot files!

1. Uncheck Hide Protected Operating Sys... in Explorer > Tools > Folder Options.
  . Copy XP boot files to root of C:\ - Ntldr, Ntdetect.com, Bootsect.dos, Boot.ini (maybe Ntbootdd.sys).
  . For safety, Rename the XP boot files in their original location (not in our new C:).
2. Enter the Recovery Console. At the prompt, type in - and press [Enter] after each:
      DIR C:
    Look for the Win9x boot files: IO.SYS, MSDOS.SYS, COMMAND.COM
    If they are found, then that C: is the drive letter we need to use with FIXBOOT.
    If not found, try DIR D:, then DIR E:, DIR F:, etc, until the correct drive letter is found.
3. Then type in - and press [Enter]     (example: FIXBOOT D:)
      FIXBOOT ?:
    where ? is the drive letter we located (the partition where Win9x boot files reside)
4. Then type BOOTCFG /REBUILD to rebuild C:\Boot.ini. Check the contents of C:\Boot.ini:
    - Win9x needs C:\="Microsoft Windows 9x". XP needs the correct rdisk( )partition( ).
6. Then type EXIT. The PC reboots. Make sure BIOS boots from C: (Primary Master).
This general principle applies if any Windows has a changed its drive letter (see Master/Slave).

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REPAIR WINDOWS Me 98/SE 95

If you can not boot into the Win9x/Me when dual-booted with XP/2000/NT:
First check the current drive letter allocation, especially if you dual-boot two hard disks.

Step 1 Check if FAT/32 is used for the PC system partition (C:) and the Win9x/Me installation drive (if different drive). Right-click the drive(s), select Properties. If it's not the correct FAT, then that's the problem - Win9x/Me can not boot!

Step 2 Now edit c:\Boot.ini, adding this line to [operating systems] section (if it's missing)
C:\="Microsoft Windows 9x"
(use Attrib -r -h -s c:\boot.ini to access boot.ini; read Boot.ini on this page)

Step 3 Then see if c:\bootsect.dos exists. If not, then create one (read Bootsect.dos below).

Step 4 Backup c:\msdos.sys (hopefully, it's there)
Boot up with the Startup Disk made by the installed Win9x/Me. At the DOS Prompt, type in
SYS C:
Press Enter. You will receive a 'System transferred' message when it has copied the boot sector and MS-DOS system files & command.com to the C: drive, thus making C: bootable. Remove the floppy.
Reboot. You will likely boot to DOS. Try c:\Windows\Win.com. If you backed up the Msdos.sys for that Win9x/Me you may be able to boot straight to the Win9x by restoring that backup.
Step 5 As a last resort, use FDISK /MBR from your Win9x boot disk to clear the MBR (does not format). Then use SYS C:. Existing FAT files should survive. This destroys an NTFS on C:.
It's said Win9x's Scandisk automatically fixes the MBR on your drive (if damaged).
Step 6 If a reinstall becomes necessary, then consider an overlay reinstall. You would still have the option of Repairing the XP/2000/NT later on (read REPAIR, above).

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FULL REPAIR OF 9x+XP/2K/NT DUAL-BOOT

Some users may have to do a very full repair. Fix both boot sectors, MBR, & files.
Example: Win9x+XP dual-boot where C: is the system boot partition.
1. Is the Master/Slave setup correct if you dual-boot off two hard disks (see below)?
  . Is C: the first Primary on first disk and marked active?
  . Are all boot files in root of C:? If not, copy them there if available. Reboot. Test.
  . Do both Wins partitions use correct file system for the Wins and the dual-boot?
  . Can both Wins read C:? If not, backup boot files for Wins to be retained, format
    the Wins partition correctly (data loss), and reinstall that Wins. Then return here.
2. If XP still boots, create a temporary Rescue Boot Disk (see below).
  . Get a Win9x boot disk (CD support) for installed Win9x. Check it for Attrib.exe,
    Choice.com, Debug.exe, Sys.com (copy from same Win9x's \Command\ folder).
  . Download THPC's Btsect25.zip (7 KB, freeware). Extract it to Win9x boot disk.
3. Boot with Win9x boot disk. Run A:\Btsect.bat and use its SYS C: option.
    Reboot. Win9x boots. If not, troubleshoot it now, or reinstall Win9x (an overlay).
4. Boot with the XP CD, or Setup disk 1 (NT users should use Inspect Boot Sector).
  . Enter the XP Recovery Console. Run these commands: (where X is the CD drive)
      FIXBOOT C:     (but read Fixboot, above, first)
      COPY X:\I386\NTLDR C:\
      COPY X:\I386\NTDETECT.COM C:\
      BOOTCFG /rebuild     (this rebuilds Boot.ini)
      If Boot.ini uses scsi(x), copy correct SCSI controller driver to C:, rename it Ntbootdd.sys
5. Exit Console. Use ATTRIB -R C:\BOOT.INI from Prompt, edit Boot.ini.
    Add C:\="Microsoft Windows 9x" to [operating systems] if absent. Reboot. Test.
6. Use   FIXMBR   from Console prompt to repair the MBR. Finished! Reboot. Test.
Finally, always create a new Rescue Boot Disk when a new dual-boot is successful! Keep it safe.

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BOOT DISKS & YOUR OWN RESCUE BOOT DISK

NEVER dual-boot without your personal safety net - a BOOT DISK for XP/2K/NT.
If stuck, boot a Win9x Startup Disk (CD support). Run WINNT.EXE from \I386\ folder on CD.

RESCUE BOOT DISK for when XP, 2K, NT will not boot - ESSENTIAL, 1 floppy
   Create a bootable floppy to get XP/2K/NT running even if the boot record,
   or boot files, are ever a problem. Write-protect and keep it safe.
      Format a floppy with that XP/2K/NT. It must be a full XP/2K/NT format.
      Alter file Attributes (Attrib -r -s -h) of these files in root of C: (PC system partition)
      Boot.ini, NTLDR, Ntdetect.com, and Bootsect.dos & Ntbootdd.sys (if present)
      (plus Arcldr.exe and Arcsetup.exe - for Windows 2K) and copy them to the floppy.
      Write-protect the floppy. Then restore original Attributes to the files on C:.
      Read the Rescue Boot Disk page for fuller details, plus a much improved Rescue disk.
Use the CD: If you have a Bootable installation CD you should check if your BIOS
   supports booting from it. This is hugely convenient, but still make the Rescue Boot Disk.
ERD XP/2K/NT: Emergency Repair Disk
   Use RDISK.EXE /S from prompt.
2K/NT Setup Boot Disks: (4 floppies for 2K, or 3 for NT)
   Use WINNT32 and MAKEBT32 from 2K/NT (\Boot disk folder on CD).
   Use WINNT and MAKEBOOT from a non-2K/NT system (such as Win9x).
XP Setup Boot Disks: (6 floppies)
   Read the Microsoft page How to obtain Windows XP Setup boot disks.
   It provides free downloads that create setup boot floppies for all versions of Windows XP.
   Each download is specific to each XP version (Home/Pro; original/SP1/SP2).
Win9x/Me Startup Disk:
   (95+) From a Windows: Control Panel > Add/Remove Programs > Startup Disk tab.
   (98+) From true MS-DOS: Go to the Command folder in Windows, and type Bootdisk.
   Windows 95 Startup Disks do not have CD support (add your CD-ROM driver).
   You can download free Win9x/Me boot disks from Bootdisk.com (IDE CDrom Drivers Included).

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#1 BOOT.INI - EDIT OR RECREATE

Boot.ini is the Windows XP, 2000, NT boot up initialization file (attributes set).

To rebuild boot.ini for Win XP:
Boot up with XP/2K's CD, enter the Recovery Console, and run:
bootcfg /rebuild
For details about the Bootcfg Command read Bootcfg Command.

To manually edit Boot.ini:
Read Edit Boot.ini for details on various methods that can be used.

A typical dual-boot boot.ini file looks like this: (use attrib -r c:\boot.ini to edit it)
[boot loader]
timeout=15
default=multi(0)disk(0)rdisk(0)partition(2)\WIN...
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WIN...="Microsoft Windows XP ..."
C:\="Microsoft Windows 98"


Explanation: (Note: The "multi(0)disk( ..." lines do NOT contain a drive letter)
[boot loader] section defines the timeout (in seconds) before the default OS loads.
[operating systems]. Each line specifies an OS to load.
  multi(m)disk(s)rdisk(n)partition(p)\directory="menu text"
  'm' is the number of the IDE channel (counting from 0). A scsi(m) would be for SCSI
  controllers without an enabled BIOS but multi(m) is still used if BIOS is enabled.
  's' is for a SCSI option and identifies which disk on controller contains the OS files (start at 0).
  'n' is the disk number on that channel (counting from 0)
  'p' is the partition number on that hard disk (counting from 1; Primaries first)
  'directory' is the name of the installation directory of that Windows
  'menu text' is just the description of what appears in the Boot Loader menu.
  C:\="Microsoft Windows 9x" This line is vital to boot a Win9x (edit it in if absent).
   The text between the quotes can be anything if it's different from other entries.


#2 BOOT.INI - ADD XP/2K/NT BOOT PATHS

Unsure of the correct syntax for a XP/2K/NT line in Boot.ini ?
All of the following lines can be added to the [operating systems] section of Boot.ini. Then keep rebooting until you select the option that works. You can now remove the unwanted new lines.
The first four lines refer to a first hard disk with up to four partitions [rdisk(0)partition(1-4)].
The last four lines refer to a second hard disk with up to four partitions [rdisk(1)partition(1-4)].
• First backup C:\Boot.ini.
• Then make timeout=30 in the [boot loader] section of Boot.ini.
• Now add all eight lines to the [operating systems] section of Boot.ini.
• Then change each WINNT to the name of the XP/2K/NT installation directory.
Place the lines after the existing similar line(s) in the [operating systems] section, but before the final line of C:\="Microsoft Windows 9x" if it exists. Save, reboot, test each option.

::: Copy the EIGHT lines below this line to under [operating systems] :::
multi(0)disk(0)rdisk(0)partition(1)\WINNT="XP 2K NT, hd1, partition 1"
multi(0)disk(0)rdisk(0)partition(2)\WINNT="XP 2K NT, hd1, partition 2"
multi(0)disk(0)rdisk(0)partition(3)\WINNT="XP 2K NT, hd1, partition 3"
multi(0)disk(0)rdisk(0)partition(4)\WINNT="XP 2K NT, hd1, partition 4"
multi(0)disk(0)rdisk(1)partition(1)\WINNT="XP 2K NT, hd2, partition 1"
multi(0)disk(0)rdisk(1)partition(2)\WINNT="XP 2K NT, hd2, partition 2"
multi(0)disk(0)rdisk(1)partition(3)\WINNT="XP 2K NT, hd2, partition 3"
multi(0)disk(0)rdisk(1)partition(4)\WINNT="XP 2K NT, hd2, partition 4"

::: Copy the lines above this line ::: Be wary of word wrap if using long lines :::

Partitions are counted from 1. All Primaries are counted first. All the above lines are for IDE, EIDE, and ESDI drives. You must change every occurrence of multi to scsi for some SCSI drives. However, multi is still used if the system uses a SCSI adapter that does not have a built-in BIOS.


#3 BOOT.INI - rdisk()partition() in the ARC path

These define the location where that Windows XP/2K/NT's folders/files are installed i.e. the OS boot partition. They must be part of one single line, and must be exactly correct! Otherwise you are likely to get 'Hall.dll', or other, errors indication the Windows can not be found. The Bootcfg /rebuild command normally handles a Boot.ini creation quite efficiently. Occasionally user intervention is required or preferred.

rdisk()
rdisk() refers to physical hard disks and starts counting from 0. Therefore rdisk(1) refers to a second disk.
Every hard disk counts, not just disks with OSs installed.
The Primary Master hard disk is always rdisk(0).
The Primary Slave has priority over any Secondary disk.
The Secondary Master has priority over the Secondary Slave.

PrimaryMaster	PrimarySlave	SecondaryMaster	SecondarySlave
rdisk(0)		rdisk(1)
rdisk(0)				rdisk(1)
rdisk(0)						rdisk(1)
rdisk(0)				rdisk(1)		rdisk(2)
rdisk(0)		rdisk(1)		rdisk(2)		rdisk(3)

partition()
A number is allocated to each partition in the order that they occur on the hard disk specified by rdisk(). It starts counting from 1, and Primary partitions on that disk are counted first.. Therefore partition(2) is the second partition on the disk.

rdisk(0)partition(1) refers to the first hard disk and its first partition. An example of the third partition on a second hard disk would be rdisk(1)partition(3).

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NTLDR and/or NTDETECT.COM are MISSING or CORRUPT

NTLDR is the Boot Loader for Windows XP/2000/NT
NTDETECT.COM is for hardware detection during boot up of XP/2000/NT

Sometimes these boot files, especially NTLDR, are missing or perhaps corrupt.
Also, Windows always considers the PC system partition to be drive C, so the drive letters on the hard disk partitions may have changed from their original orientation.
First try to Repair XP or Repair 2K/NT (see this page).

To replace a damaged/absent NTLDR and NTDETECT.COM:
These two files are not PC-specific.
You can copy fresh files from any XP CD. The procedure will be similar for Windows 2000 & NT.

• Boot with the XP CD, or Setup boot disk 1, and enter the Recovery Console.
• At the Command Prompt type in: (press Enter after each line)
   COPY X:\i386\NTLDR C:
   COPY X:\i386\NTDETECT.COM C:
   Exit
   (where C: is the PC system partition, and X is your CD-ROM drive letter)
• Reboot.
If the partition was not formatted using Windows, you may also need to use the Recovery Console's Fixboot command to make the partition bootable.
If this corrects the XP situation, you can then (if necessary)
Edit BOOT.INI to add C:\="Microsoft Windows 9x" to the [operating systems] section.
• Check if Bootsect.dos is present in root of C: (read Boot.ini & Bootsect.dos on this page).

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BOOTSECT.DOS Created if Missing or Corrupt

Restore BOOTSECT.DOS, or create new one, in a XP/2000/NT + Win9x/Me dual-boot.
BOOTSECT.DOS contains the boot sector for Win9x/Me in a dual-boot with XP/...
This Win9x boot sector file (bootsect.dos) is only used if Win9x is selected from the XP/... Boot Loader menu on boot up. Obviously Win9x can not boot without it. Bootsect.dos is created during the XP/... installation if Win9x is installed first. It may be missing or corrupt. Also, you sometimes need to create Bootsect.dos if XP/... is installed first, and Win9x last.

1. First check if FAT or FAT32 is used for the PC system partition (C:) and OS boot partition (if different). Right-click the drive and select Properties. If it's not the correct FAT/32 file system, then that's the problem and restoring Bootsect.dos will not help.
2. Then try repairing the XP/... boot sector - see this page. This may restore Bootsect.dos

3. Make your own Bootsect.dos:   (read the Bootsect.dos created new page)
Use this only if C: is the PC system partition, and Win9x boots normally without a menu (though you can use the SYS C: option in Btsect.bat to make it so, and the repair will later fix the XP/2K/NT C: boot sector).
The SYS option creates a NEW Win9x/Me boot sector on C: before Bootsect.dos is created.
• Download Btsect25.zip (6 KB, freeware) from THPC here (extracts to 17.9 KB).
• Unzip its 3 files to your boot up floppy for installed Win9x. Add Choice.com to a Startup Disk.
   Other Win9x boot disks must contain Attrib.exe, Choice.com, Debug.exe, Sys.com.
• Boot up to true MS-DOS with that Startup disk, and run
     A:\Btsect.bat
     Use the SYS option only if appropriate. Then Debug creates a new C:\BOOTSECT.DOS file.
     An existing c:\Bootsect.dos is first saved as c:\Bootsect.PRV. Boot files are also backed up.
Win9x will boot normally. When XP/2K/NT is repaired it will boot, and dual-boot with Win9x.
Note: Bootsect.dos is a Read-only, Hidden, System file (+r +h +s) on the root of C:\.

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REINSTALL A WINDOWS - AN OVERLAY REINSTALL

How to Repair Windows XP by installing over an existing installation:

At some stage you may simply have to reinstall a Windows!
A clean reinstall, especially for the home user, is normally recommended by THPC (but first save all those setting, etc!). However, when dual-booted, an alternative is tempting at first attempt.

All versions of Windows can be reinstalled over the existing setup. You can expect to retain all your installed applications, data, and settings. Always backup important data first, just in case!

Win9x/Me Reinstall:
• Backup those boot files (read Boot files, this page)
• Just install it over itself in the normal manner. Retain newer files (unless you know otherwise).

WinXP/2000/NT Reinstall:
Windows XP is used as example. Windows 2000 & NT will be similar.
• Boot up with the Windows XP CD, and continue the install.
• Press R to 'Repair the selected Windows XP installation'.
• Windows XP copies files to your Hard Drive and reboots.
Do not press any key when you see the message 'Press any key to boot the CD'.
• In a few seconds Windows Startup Screen will be displayed, and then the Setup Screens.
Reinstall - similar to the first occasion.
• Backup those boot files (read Boot files, this page)

All your previously installed applications and settings should remain intact.
Read Microsoft's How to Perform an In-Place Upgrade (Reinstallation) of Windows XP

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BOOTUP SEQUENCE

A basic understanding of the boot process, and system file structure, is helpful.
This describes the boot up sequence as dictated by standard BIOS/CMOS settings.
Boot up uses the 1st sector of the 1st physical hard disk, or floppy, or bootable CD.
Start PC > CPU > BIOS [> POST] > 1st sector > MBR (it's not OS, or file system, dependent).
BIOS copies the MBR (Master Boot Record) into memory. The MBR contains the Partition Table and MBP (Master Boot Program). The MBP looks in the Partition Table to identify which partition is marked active and loads the boot sector of that active partition into memory (this is OS, and file system, dependent). The active boot sector now has control, and runs the system boot files for the corresponding OS. Finally, that OS loads.

XP, 2000, NT Dual-Boot Process:
The boot up is similar except that NTLDR is run. NTLDR runs the Boot Loader menu which shows the operation systems available in Boot.ini. If Windows XP/2K/NT is selected, NTLDR loads the boot sector of the active partition into memory and runs XP/2K/NT.
If MS-DOS/Win9x is selected, NTLDR loads Bootsect.dos into memory (Win9x boot sector) - this bypasses the boot sector of the active partition, allowing Win9x to be run instead of XP/...

Remember the FAT, FAT32, & NTFS PITFALLS:
• The PC system partition (C:) must use FAT/FAT32 in most Win9x dual-boots.
• That PC system partition (C:) AND Win9x boot partition (if different) must be same FAT.
• A Win9x can not boot from an NTFS partition!
• A Win9x installation attempt on an NTFS partition may damage that partition!
• The maximum partition size when using the FAT16 system is 2 GB.
• XP & 2K use NTFS and FAT16 & FAT32.   • NT uses only NTFS & FAT16.
• Me, SE, 98, 95OSR2(+) use FAT16 & FAT32   • 95 & 95a(OSR1) use only FAT16.
• NT uses a different NTFS from XP/2000 unless updated with Service Pack 6a.

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BOOT FILES FOR WIN XP 2000 NT & WIN9x/Me

Take good care of your Boot files and BACK THEM UP WHEN TIMES ARE GOOD!

The boot files for an installed Windows are on the root of the PC system partition. This is nearly always C:, the first partition of the primary drive. This is also where a Win9x/Me boot partition rests most comfortably and it must be FAT/FAT32. The Win9x/Me files can be installed on any other FAT/FAT32 partition, but that OS boot partition must not be converted to NTFS. Many boot files have Hidden, Read-only, and System file attributes. Read Notes, below.

Under a Win9x/Me + XP/2000/NT dual-boot, the Win XP/... is always in control of the boot (nearly always the C: drive). The PC system partition must remain a FAT/32 file system when a Win9x/Me is in the dual-booted (unless using a third-party utility).

It is safer, and advised, to backup the current boot files of an existing Windows before installing the next Windows. And then backup all boot files again after a successfully new installation.

Win XP/2000/NT Boot Files:
• Boot.ini, Ntldr, Ntdetect.com, Bootsect.dos, (maybe Ntbootdd.sys, Arcldr.exe, and Arcsetup.exe).
   Bootsect.dos is created by a XP/... install/repair when it recognizes a pre-existing 9x.
WIN9x/Me Boot Files:
• Io.sys, Msdos.sys, Command.com, (also Drvspace.bin), and maybe Autoexec.bat & Config.sys.

Ntldr and Ntdetect.com are not PC-specific and can be copied from any CD or PC.
Boot.ini is PC-specific, but can easily be created, or edited if copied from another computer.
Ntbootdd.sys is specific to a SCSI controller but can be copied from a PC that uses the same.
Bootsect.dos is PC-specific, and cannot be copied. Back it up when it is valid! A Repair may recreate a valid Bootsect.dos. Use Btsect25.zip to create one if other methods fail.

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XP CONSOLE

How to access the XP Recovery Console: (NTFS)

The Recovery Console provides some useful tools which run from a Command prompt. These tools can help sort out some problems.

Go to Start > Run and enter "CMD" to open a Command window.
Type Help to see a list of functions.

To run the XP Recovery Console from the CD:
You should become familiar with this even if you are not dual-booting - just don't actually run anything until, and if, you need to do so.
• Boot up with the Windows XP CD (or with the six floppy Setup disk set)
• Select R at the Welcome Screen.
• Press 1 (presuming you have just one XP installation).
• Press Enter for your Administration password (it's blank by default).
• Type Help at the C:\Windows Command prompt for a list of commands you can use.

How To Exit the Recovery Console:
Type Exit at the Command prompt and Windows will be started
(you can't use Ctrl+Alt+Del to exit the Recovery Console).

For information about the different commands and their functions:
Read
Recovery Console

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MASTER / SLAVE & CABLE SELECT (CS or CSEL)

Cable Select may be a problem if a Dual-Boot breaks down.

Traditionally the Master and Slave has always been selected by physically changing jumpers on the hard disk itself. When the Cable Select pin is set, it's the cable (connector used) that determines whether it will be Master or Slave. The purpose of Cable Select is to allow simpler configuration. It usually does not cause any problems in a dual-boot.

However, that situation may change radically in some instances where there is a dual-boot fault / repair. Its been reported that a repair of XP had led to Master and Slave being swapped! This could be the cause of many failed dual-boot repairs where two hard disks are involved.

If your Windows are on two hard disks, you should first check that the original configuration has not changed (use Diskmgmt at prompt in XP).

You may need to stop using Cable Select, and use the jumpers to set the disks to the original Master and Slave configuration. Also, make sure there is no BIOS/CMOS setting enabled to use Cable Select. When you set the drives to Master and Slave, the Cable Select (CS or CSEL) signal will be ignored by the drives. It is only then that you can expect to execute a successful dual-boot repair if this problem applies to you.

Example:
WinMe is on C: (Master, bootable, FAT32) and XP is on D:, a second hard disk (Slave, NTFS).
WinMe is reinstalled on C: (for a variety of reasons, such as a virus).
An XP repair would be expected to fix the dual-boot (especially if Bootsect.dos is created before the repair). However, D: may now be the Master with C: as Slave and that needs correcting.

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FORMAT or PARTITION FROM XP CONSOLE

How To Format with XP:
• Go to Start > Run and enter "CMD" to open a Command window.
• Type in
   format drive : /Q /FS:file-system
   where
   drive is the drive letter of the partition to format,
   /Q performs a quick format
   /FS:file-system specifies the type of file system to be used [FAT, FAT32, or NTFS].

Examples:
FORMAT C: /Q /FS:NTFS - a quick format of the C: partition as NTFS
FORMAT C: /FS:FAT32 - a full format of the C: partition as FAT32
If no file system (/FS:xxx) is stated, then the existing file system format is used.

How Partition with XP:
• Go to Start > Run and enter "CMD" to open a Command window.
• Type in
   DISKPART
• Press Enter.
• You can move through the display using the Arrow keys.
   Press C to create a partition in unused space.
   Press D to delete a highlighted partition.

Windows 2000 & NT will be somewhat similar.

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NOTES

Active: Four Primary partitions per disk can be recognized but only one Active partition can exist. Win9x does not like more than one Primary per disk.

Identify Which File System is being Used:
Double-click My Computer on desktop. Right-click the disk you want, then click Properties.
Look for the File System entry.

View File Attributes:
Double-click My Computer on the desktop.
Click Options on the View menu. Now click Show All Files.
To view file name extensions, clear the Hide MS-DOS extensions for file types that are registered check box. Click OK.
Right-click a file in Explorer, and click Properties, to view & alter its Attributes (not System; that must be changed from DOS; so use attrib -r -h -s c:\msdos.sys from DOS of some sort).

Change File Attributes:
In Windows Explorer, click Folder Options on the View menu.
On the View tab, click Show All Files , and then click OK.
In Explorer, right-click the target file, and then click Properties.
Click to clear the Read-Only and Hidden check boxes if checked, and then click OK.
The System attribute must be changed from DOS (attrib -r -h -s c:\boot.ini).

Restore File Attributes (example):
Open a DOS Prompt, and type (then press Enter):
attrib +r +h +s C:\boot.ini
using only the attributes identified and changed earlier.

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Please remember that you alone are responsible for the consequences of any changes you make to your computer hardware or software.

Copyright © LarryM 1998-2015 thpc@mail.com