Quick, Multicolored Bars/Freezing

When I play in windowed mode in a few games (awkwardly enough, it is two space-based games with black backgrounds, starfields, etc.) very briefly every now and then I will see a very quick flash of thin, horizontal bars that are all colored differently on my screen. They will continue until eventually my screen completely freezes and I must restart by my tower. When I play fullscreen, this doesn't happen. Why?

Here is information regarding my hardware: http://www.xfire.com/profile/crayder/
(at the bottom, Gaming Rig)

 

If two different games I wonder if it might have something to do with the games trying to change the screen resolution to their default settings . . . and are conflicting when you switch back and forth.

I had a similar screen issue when using a KVM switch and the PC's had slightly different video settings (but identical video cards) . . . not the same as two games, but the colored bars sound exactly the same.

Just a shot in the dark . . .