Swapping Motherboards
If you don't wish to perform a clean install (fdisk, format, reinstall Win), under Windows 9x systems (including Windows Me) you can force the system to redetect all your devices by deleting a key in your registry. To do this, go to Start, Run... and type regedit. Under HKEY_LOCAL_MACHINE delete the folder Enum and all its subfolders. Windows will redetect all the necessary hardware devices when you reboot (you may have to reboot several times before it finishes recognizing all the hardware ). This should be equivalent to performing a clean installation - but obviously this is not as thorough as formatting the disk and starting again with a clean install. Remember that if anything goes wrong with modifying the registry, Windows maintains backups in C:\Windows\SYSBCKUP in the files rbxxx.cab. If disaster strikes, you can always boot into DOS with a floppy and then restore your registry manually by extracting the files from one of these CAB files (using the Extract command located in C:\Windows\Command)
But better do a Ghost first!