Problem with games! (SS)

[Spielwurfel]

My PC was working fine, but suddenly it stopped running games! Everytime that I run the "3D" part of the game, the screen turns black and nothing happens... Then an error message appears...
This appeared when I tried to run 3DMark 2006:

What can I do to solve it?

 

[monkey_knife_fight]

It looks like an issue with your video card driver. Is it just with games (and 3DMark)? What kind of video card are you using? What version of DirectX?

 

[Spielwurfel]

My PC is a P4 1.5 Ghz, 512 Mb Rambus memory, GeForce 6200

I already reinstalled the driver (using the Driver Cleaner), and reinstalled DirectX...

It happens in all games... But... Usually appears that the memory couldn't be written or read... But I already tested the memory (with a trustable program) and is said it's working with no problem...