Direct3D error - Radeon 9600xt - Won't run any 3D games- need help

[unnam514]

Ok i have a radeon 9600 xt 128mb ddr. Whenever i try to run a game (like Project 64 or Lotr Return of the King) it says that it couldnt find a compatible Direct3D device or that it doesnt have the required capabilities. I have tried installing the Drivers from the Return of the King Cd, but still nothing runs. My brother said it was probably a corrupt Direct 3D and that i would have to go through the registry to find it or something, but i really dont know what to do. plz help