Heres a much better way to switch motherboards under Win2K or WinXP without reinstalling Windoz:
1. Backup your C drive, or, at the very least, all data files on C drive. Its very unlikely you could screw up the other partitions, which is one reason I like to keep C only 4 GB or so and instlal software on other drives.
2. Acquire a Promise IDE controller, follow directions to add it to your existing system (old motherboard). Usually this means installing the controller, not connected to any drives and inserting the Promise floppy when prompted by the OS.
3. After turning off, reconnect your IDE drives to the Promise controller -- it should reboot with no problems
4. Now move everything over to the new motherboard, with IDE drives still hooked up to Promise. Its probably a good idea to delete the USB devices, default IDE controller and anything with the chipset name in your system devices, although I forgot to delete the IDE controller (don't delete the Promise!) and the procedure still worked.
5. When you reboot, Windows will be able to boot and it will detect the new chipset and devices. Its probably better to cancel out of everything and run the motherboard "install" CD
6. Reboot, and check that everything looks OK. Then turn it off, remove the Promise controller and hook everything back up to the motherboard IDE ports.
7. You can now unacquire the Promise controller
I successfully moved from an K7S5A to an Asus A7N8X using this procedure. The method of deleting system devices and then trying an installation "repair" DID NOT WORK, but this method did. It it won't boot in step 5, try booting the Windows CD and repairing the installation. That may be a more fail-safe way, and you stand a much better chance of a successful repair, since Windows does not NEED the device drivers of the new motherboard to access the boot device and CDROM.
Probably any PCI IDE controller will work. The basic idea is that Windows needs to have any device drivers for its boot drive and the CDROM drive already installed when switching motherboards.