you have to check the manufactures website to see if they released xp drivers for your machine! .
*** Most of the newer machines/laptops are not releasing xp compatible drivers! ***
*** If your manufacture does not have XP drivers I suggest you leave Vista on the machine ***
1) Check your manufactures website support page and download ALL XP drivers if available.
2) Burn ALL drivers onto a CD (and test CD has burnt properly)
3) Install XP.
4) Run windows update, and install ALL updates
4) Then install the drivers that you burnt onto a CD.