I have the EXACT SAME PROBLEM. But I can say that it is not hardware related: For me, it started right when I downloaded the full version of a game that I already had a demo for (the demo worked fine). Case and point, it can't be the hardware. I think it has something to do with the corruption of the graphics card because I also have a graphics card from the same manufacturer (and windows 7). Sorry, no solutions: I am looking for them, though. But I know nothing about PCs so don't ask me.