This can occur due to various reasons, but normally its because you've changed something recently which Windows doesn't know about yet.
Windows XP and SATA drives with AHCI enabled
Most common scenario I've seen is the use of AHCI in SATA drives (a BIOS setting) causing this to occur. This is because Windows XP is a decade old and does not ship with Intel's AHCI drivers.
a) Manual fix
- Disable AHCI in the BIOS.
- Install Windows.
- Manually install the AHCI drivers.
- After that, you can re-enable AHCI.
b) Slipstream AHCI drivers into Windows setup
If you do not have access to change the BIOS settings, then you can slipstream the AHCI drivers into the Windows XP setup.
For XP, you can use nLite. It's a great little piece of software thats free and comes with a bundle of options.
I've written a guide on how to do this as part of another tutorial. See the section "Slipstreaming Windows XP Installation Disc".
Note: Intel has now renamed AHCI ("Intel Matrix Storage Manager") technology to "Intel Rapid Storage Technology" (Intel RST). A list of other names here.
Using an external USB CD-Rom device to boot/install Windows
After installing Windows with an external drive, you may encounter this problem when rebooting.
See Microsoft KB883114 about how to fix it.
- Intel AHCI/RST drivers (x86 or x64)
- Intel AHCI/IMSM/RST product name changes
- Use a USB CD-ROM device to install Windows Server 2003 or Windows 2000