You should be allright since you're running win2k now. The boards chipset might be a problem, like DosFreak said but don't expect much bigger problems than the ones you have in win2k with it.
Also do NOT try to upgrade from win2k to XP, it's usually a bad choise.The system is always better with a clean install, unless you really can't be asked to do that.
P.S. If i understood well from your Name in the forums, you are a game fan, so that's good news for you: Installing XP will give you a significant boost in multimedia apps (mainly games)-just hope that Nvidia has made some good work with the drivers.