Graphic problems after 10.5.3/10.5.4 (?)

[crawle]

Hey guys,
in the last weeks I updated my system two times, 10.5.2 to 10.5.3 and 10.5.3 to 10.5.4. It seemed to be working at all, but now, after a few weeks of working and playing (games) on the updated system, I see many graphical problems. For example, when I play World of Warcraft, the screen freezes after a time, sound is working normal, mouse is moving. I close it by press CMD+ALT+ESC and my dock looks like this:
(see attachment)

And sometimes even my the desktop becomes strange, there are cords and that stuff, but when I do something in this area of screen, they disappear. All that is happening only after playing a game (usually). So whats up with my graphics?

By updating to 10.5.3 a few weeks ago, I also updated my NVInject stuff (edited them like described in many tutorials), but QE/CI is working actually.

Have you got an idea, whats wrong with my system?

Greetz,
-crawle.