1)Try to reinstall your video card drivers
2)Check if Directx is propaply installed by runing DXDIAG if not reinstall DirectX9.
3)If this problem is with these two games only, Unistall them from add/remove program and then reinstall them
4) try to update your AGP drivers ( intel or VIA )
5) if you still experience the same problem Formating your Hard drive and instaling a fresh copy of winxp will do the job :Oo:
6) if the problem persist then the problem is with you Buddy !!!