when you have formatet should you as a standard rescue, make patitions on your HD, one for you OS, and one for games and drivers Etc. then you will allways have your Drivers, games and all your stuff on your HD.
do you have DVD-burner? if you have you should make a "rescue" disc with every thing you want to save, after that you shall reboot your machine and put the XP-Disc in your CD-drive and then it will automaticly ask if you want to start : Windows XP installation or if you want to start Windows Xp(remember, you MUST NOT put the XP-disc In the CD-drive before your comp. has turned off, becuase then the Program put's instalationfiles on your HD, and then you can't make a format directly from the Disc) choose Windows Xp Instalation - after a while(i presume you can reach as far as that) it will look after a former WIN. now you shall delete the partition were windows were before, after that you command the comp. to make a new patition
(only for Windows, remember that). now install, choose NTSF(No NTSF/quick.. becuase that is only a quick format, choose NTSF, and push enter, now your comp. will start formating, and begin Win Xp Instalation..
hope you can use my advice..
my regards
Philip