Have you tried reinstalling DirectX? I once had a similar issue and I'm pretty sure that solved it.
Do games work?
Michael: Jodie, how's my schedule look for today? Jodie: You've got a conference and dinner party at the Japanese Embassy regarding wildlife protection. Michael: Oh, yeah...sorry, but I'll have to cancel that. I'm heading out to save America!
Just downloaded and installed DirectX. Now we get beyond my limited understanding - it appear that DirectX is no longer the default (what? language? program? plugin?) for any video-related operations. Many of my games and screens look (subtly) different and run much more slowly. is it possible to set DirectX as the default for everything video-related?
Both FF 4.0 and IE9 were not showing anything - had to disable hardware acceleration to get them to work properly. VLC was fixed by resetting output module to DirectX, the default (how I changed that I have no idea).
Right now the only thing that does not work properly is Windows Media Center - will play videos in full screen only. Any minimization results in black screen.