For some reason today, when I load graphic intensive apps (i.e. games), the textures will flash with checkered boxes then my system will crash. I have updated my gfx drivers but problem still occurs. I used dxdiag to test my Direct3D and DirectDraw and no problems found. I thought it was the specific game, but found out it was all games that I tried. It was working fine yesterday. I don't think the gfx card is overheating either. What can I do to fix it?
[Edit] My gfx card is an ATi X800GTO
[Edit2] I managed to take a screenshot of what happens. I've identified the problems within the red squares