   Testing for a bad video card
  Hello,My computer freezes after a computer idle and sometimes randomly.I've done some preliminary RAM tests and it's suggesting it's not the RAM, but I'm going to run memtest86 all night to see if there are any errors.Tech support for my machine suggests I test for a bad video card. How do I do that? Both of my video cards function as I think they should (for normal desktop stuff). I haven't tried a game yet.How do you normally test a video card? 3dMark?   
  Google showed up this: http://freestone-group.com/video-card-stability-test.htmno idea if it's any good.Toolmaker   ;  That sounds like the problem I'm having.  I can't help but wonder; if the video card freezes the computer, won't any of these video card tests just cause the computer to freeze?   ;  There might be something in the log after a crash.When mine was causing problems I did a fresh install and just used the default drivers that come with windows.  I had no problems then, so it meant the card wasn't working beyond basic functionality.  Got a new card and problem solved.If you can isolate the exact cause of the freezing you can deduce if it's the card or not;  For me, I found that anything that utilized the card's capabilities caused crashes, like running rendermonkey or even an OpenGL Screensaver.  Good luck   