could not load opengl subsystem

ok, I played quake 3 and mohaa in my pc before with win98... i upgraded it to xp and i cam only play quake!! when i try to load mohaa this message appears: could not load opengl subsystem.... help me!!!please!!!!!

[1234!]

The drivers that come with XP dont support OpenGL.

You have to go to the website of the manufacturer of your 3d card, and download/install the latest drivers for your card.

i tried to download the nvidia drivers cuase i am having the same problem...i instllaed them...restarted and it still didnt work and my OpenGL test system said something was SCREWED UP!!!! HELP!!!