And ...

once you have your 4 XP's booting again (or not even booting), you might find you need to tell it about the new motherboard and SATA drive. http://michaelstevenstech.com/moving_xp.html gives the 25 steps procedure. Also you might find http://arstechnica.com/gadgets/2007/09/how-to-install-a-new-motherboard-without-reinstalling-windows/ interesting to read.

Kees