ATI Radeon 7500 w/WinXP ... OGL not working!

I just got an ATI Radeon 7500 today, I installed it and everything… but everytime I try to run Half-Life (CS, DoD, etc.) it won’t run in OGL… I dowloaded the update for the driver, but that won’t run cause it says that it’s not compatible with the display driver… I got it from itself!! Any suggestions?