Maybe it could be Vista?
Try re-installing your graphics card drivers, if that doesn't help, I have no idea what is wrong.
Yeah, like I said, it only happens in Software.Is it fine in OpenGL?
That doesn't do anything except bring up the start menu as usual. I think you may have misunderstood the problem.I have this too try the menu key on your keyboard
What version of DirectX are you running?
DirectX 9, 10 or 11?