Does the system right now have a botable OS on it? If so...first thing I will need to help you is for you to restart the computer...As soon as you see anything on the Black screen hit the pause key. Now in the lower portion of the screen you will see a long BIOS string of information. Write down that string and everything/anything else on that screen.
Type it all nice and neat back here (make sure you are very accurate here as it is very important so we can identify your board manufacturer and get the proper BIOS Flash Update.
I will research the BIOS update needed, and if you can also install right now Belarc Advisor (from www.belarc.com), run it and copy and paste the results of the current inventory I willalso research the updated hardware drivers (do though list any hardware changes you will be making once you do load up XP so we can get all the proper drivers together). I will send you via e-mail a list of links where the drivers reside along w/ a few utilities that really work.
Will you be wanting to dual boot the system? Do you know how to partition & format properly? Have you got a CD from MS that tells you what hardware & software you currently have on your system that will work w/ XP? (No worries I do and can let you borrow it).
Do you want it to be a standard setup or a killer setup? What are the main purposes for the system...Browsing, Gaming, Office Applications....Etc., etc.
