as far as I have tested doing a swap like this ,if you have no special hardware, you need the xp disc
go through the setup to the last part to repair the drivers for the diff MB's
worst case you will have to reactivate the OS
I test to much hardware on my machines xp would barf it up
even my W$K will give HAL errors ,but I can control that,this is why I don't use XP.
Good Luck