[Cactus]

Hya,

These blue screen after a motherboard change are normal. The are most often generated because the bootcontroller is not exactly the same as on the old board.

You can prevent it by adding the drivers for the new motherboard befor you do the actual switch. If the OS is booted with the old board it just errors that the newly added drivers don't work because the hardware isn't functioning. After swapping the board XP will still error about drivers, but now it the old driver that doesn't work. But booting XP shouldn't be a problem.
HP Navigator CD's do this trick by default; it installs drivers for every SCSI/IDE controller that Microsoft has. This way the disks can be put in another system in witch it probably will boot without problems.

Of course your BSOD might be caused something else, please tell us the Stopcode, this give us a change to look further . . .

Cheers!