open GL not supported

I just cant seem to find the problem, hopefully you guys can help me out. This problem started just after direct x 9.0b and c came onto my computer. For games such as half life 2 it no longer runs correctly. When it starts the game just loads, quits, starts in a new window with less pixels, does it a few more times, then finally quits saying Open GL not supported when it should be. I think this problem is also related to why all video files played on the computer are distorted, they are all the wrong colors and are usually bright and hard to see. Tell me what info you need, or if you know what i can do.