I've been having a problem with either my screen or my
video card...I think.  When I do anything with my
computer after a few seconds it freezes for a couple of
seconds then the screen goes black for a few seconds
after that it's almost as if it refreshes itself. I can't
play games or video because it freezes for even longer.  
What could be the problem?  I've downloaded the newest
video card driver and that didn't do anything. Please
Help.

               Thanks,
                Josh