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How to replace the first Hard Disk

Last reviewed: April 2005

You can replace the first hard disk (Primary Master, harddisk0) and still boot to Windows XP/2K when XP/2K is installed on the second disk (harddisk1). This a safe procedure because the second disk, where XP is installed, will remain unchanged. Also, in the event of some unforeseen circumstance, the original first hard disk can be returned as Primary Master and nothing will have changed.

The principle involved here relates to situations where Windows XP or 2000 is installed on the second hard disk and the PC system boots, initially, from the first hard disk. That means:
  • the XP/2K boot files (hidden files like NLTDR) are on the first partition of the first hard disk,
  • and the XP/2K folders/files (Windows directory) are installed on the second hard disk.
This situation can exist when dual-booted, or even if no Windows is installed on the first hard disk.

Do not use these instructions if using a third-party boot manager (like BootMagic) , or hard disk management software (like OnTrack Disk Manager or Micro House EZDrive).

Replace 1st hard disk and still boot to XP/2K installed on a 2nd disk

Example used here:

• Win98SE is on C: (1st hard disk - Primary, Active, PC's system partition, using FAT32 on Primary Master disk)
• XP/2K is on D: (2nd hard disk - Primary, Boot partition, on Secondary Master or a Slave disk).

Suppose you have two hard disks, each with just one partition (C: on the first disk, and D: on the second). Windows XP/2K is installed on D:. However, a Win9x is on C: and you want to replace that small, failing, or damaged, hard disk. This scenario can also exist when no Windows is installed on the first hard disk and XP/2K is installed on the second hard disk.

You may, or may not, wish to reinstall the Win9x on the new hard disk (but read Bootsect.dos first if reinstalling Win9x).

Simply replacing the first hard disk will stop XP booting. That first hard disk is used early in the boot up process and the new one needs adjustment to allow XP to run from the second disk.


The (first) partition on the first hard disk is currently marked active, it is the PC's system partition, and it contains the XP/2K boot files required to run Windows XP/2K from the 2nd hard disk. The new first hard disk must be made to copy these three essential items. The Recovery Console on XP/2K's CD, and a Win98+ boot disk, will be used without needing to boot any Windows until the procedure is complete.



1. CD for Windows XP installation.
2. Boot disk, or Startup Disk, for Windows 95b+ (Win98 or 98SE is best)
    (it must have CD support if your BIOS does not allow CD-ROM booting)
3. These instructions!

Summary of Procedure:

Replace 1st hard disk with replacement hard disk as Primary Master
(Fdisk, and Format C: /S, if necessary, and reboot).
Boot up from Win9x boot disk and use Fdisk (Option 2) to mark new first partition as Active.
Cold boot to the Recovery Console (with XP/2K's CD).
Use MAP command to identify the letter for new Harddisk0Partition1
  (change C:, below, if it's not C:).
Copy NTLDR and NTDETECT.COM from the i386 folder on the XP/2K CD to the root of C:
  If using 2K, also copy ARCLDR.EXE and ARCSETUP.EXE from i386 to C:
Use FIXBOOT C: (to fix the PC's system partition)
and BOOTCFG /REBUILD (to rebuild Boot.ini)
Reboot. Finished.

Detailed Procedure:

Before you start
Your computer must be able to cold boot from XP's CD. If it does not, you will have to reboot and access the computer's Setup (or CMOS or BIOS) early in the boot up by pressing a specific key (you'll see a prompt on-screen telling you which key to press). In the BIOS, the CD-ROM must be a boot option, and this option must come before hard disk (IDE_) boot options - save any BIOS changes as you exit, and reboot.

If a CD-ROM boot option is not available in your BIOS, you can use XP's Setup Disks (How to obtain Windows XP Setup boot disks), or a Win98+ boot disk (, to access the Recovery Console. Read Boot from a bootable CD for full details on booting from a bootable CD.

1.0 Replace first hard disk with new hard disk as Primary Master (set the jumper/cable correctly).
2.0 Boot up with a Win98+ boot disk inserted
2.1 Skip to 2.2 if, for some reason, you don't wish to Fdisk & Format the replacement hard disk.
      - Type in Fdisk
        Confirm that FDISK options says Current fixed disk drive: 1. Then select option 1.
        Create a Primary DOS partition (make an Extended partition, then Logical partitions,
        but ONLY IF your XP/2K is on a Primary partition on the second hard disk).
      - Use Format C: /S when finished with Fdisk   (note the space before the /S)
        (press Y for Large Disk Support - that's for FAT32)
      - Remove the boot disk and Reboot (to a DOS prompt).
2.2 Boot up again from the Win98+ boot disk
      - Use Fdisk (Option 2) to make the new Primary the Active partition (the A under Status).
      - Press ESC to exit Fdisk, remove the floppy, and reboot.
3.0 Skip to 4.0 if not installing a Win9x on the new hard disk.
      - Install a Win9x on the new C: now.
      - You can save the Win9x boot sector now - just in case! (Bootsect.dos shows you how)
4.0 Cold boot from XP's installation CD to the Setup screen (or read Boot from a bootable CD).
       (press the appropriate key when requested to boot from the CD,
        or check in the BIOS for something like 'Boot Order' - the CD-ROM must be before hard disk).
      - Press R to enter the Recovery Console
          Press 1 for Which Windows installation ... (presuming there's just one)
          Press [Enter] for Administrators Password (it's blank by default)
4.1 Type in MAP and press [Enter]
      - Identify the drive letter allocated to Harddisk0Partition1 (it's probably C:)
        (if it's not C: then replace every C: below with the correct letter)
      - Type in these commands, pressing [Enter] after each
        (but change Z to your CD-ROM drive letter)
          COPY Z:\I386\NTLDR C:
          COPY Z:\I386\NTDETECT.COM C:
          COPY Z:\I386\ARCLDR.EXE C:   (only if using 2K)
          COPY Z:\I386\ARCSETUP.EXE C:   (only if using 2K)
          FIXBOOT C:
            press Y to confirm
            press Y for Add installation to boot list
            type Windows XP for Enter Load Identifier
            type /FASTDETECT for Enter OS Load Options
        (note the space before each Z:, before each C:, and before /REBUILD)
5.0 Finished! Remove the CD.
      You will reboot to XP (on the second hard disk)
      and will have access to your new first hard disk.

Tip: Create this Rescue Boot Disk for XP/2K when all is well - you may be glad some day!

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Drive Letters
The letter allocations shown in the Recovery Console are not always the same as those shown in Windows XP/2K. If using a letter in the Recovery Console it must be the letter shown by the Recovery Console itself. Usually the letters are as expected, but occasionally there is a difference. The MAP command shows the letter allocated to each partition by the Recovery Console. Hard disks start counting from 0. Partitions start counting from 1.

    Harddisk0Partition1 is the first partition on the first hard disk.
    Harddisk1Partition1 is the first partition on the second hard disk.
    Harddisk1Partition2 is the second partition on the second hard disk.

Harddisk0Partition1 is normally the PC's system partition and is usually allocated the letter C
Harddisk1Partition1 is XP's boot partition in the example shown here.

Window 9x allocation of drive (partition) letters was always very rigid - we got exactly what we expected. Windows XP allocation of drive letters (as seen in Windows itself) is more fluid - it allocates according to its own perceived need. For instance, if you Format a partition during XP installation, and do not reboot immediately before continuing installation, you may later see a drive letter that's different from what you expected e.g. XP may show as being installed on G or H instead of on the expected E! Windows XP copes with this discrepancy in its internal operations and, if there is a difference, it will be reflected in the Recovery Console. Concentrate of the Harddisk number and then the Partition number to identify the letter allocated.

Windows XP/2K will not format FAT32 partitions larger than 32GB. Use a Win98/Me boot disk to do this.

Always reboot after formatting and/or creating a Active partition. If you do use the XP/2K installation to format a partition, be sure to reboot before installing the Windows. This should stop XP/2K messing with the drive letter allocations.

A new Boot.ini is created in the above method so an edit of Boot.ini should be unnecessary. However, read Edit Boot.ini in Windows or MS-DOS if you need help in this area.

SCSI controller
Ntbootdd.sys may have been present on the first partition of the old hard disk. Ntbootdd.sys is a renamed device driver for a SCSI controller. It can be copied from the replaced hard disk or from a PC that uses the same, or, if identified, can be copied from the CD and renamed to Ntbootdd.sys. If a line in your original Boot.ini used scsi(x), you should resolve this before you start. It will not arise if you have a desktop or tower PC.

Reinstall Win9x
If re-establishing a Win9x dual-boot, do not be tempted to save the existing C:\Bootsect.dos for later use. It will not work. That original Bootsect.dos contains a Partition Table that will be different from the Partition Table for the new disk. Read Bootsect.dos to create a correct Bootsect.dos if you intend installing or reinstalling a Win9x (see 3.0 above).

Also, if retaining Win9x, you must later add the following line to the [operating systems] section of the new Boot.ini on C: to make a Win9x boot option appear in the Boot Menu on boot up.
C:\="Windows 9x"
(you can use anything you like between the quotes, like WinMe. However, you must use the quotes, like C:\="WinMe")

Which XP/2K
If you are repairing a computer that has more than one XP/2K Windows installed on the second hard disk, from the Recovery Console choose the Windows XP/2K installation that you need to repair. Also, remember the Recovery Console recognizes only XP, 2K, and NT. It ignores any Win9x.

The command FIXMBR can be used in the Recovery Console to repair the boot drive's Master Boot Record (MBR) of the Windows XP/2K you are logged on to. However, Fixmbr should be used only when a problem with the MBR is evident.

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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.

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