For the second time in a few days now (I think it may have happened once before, I forget) my MacBook, pretty new (bought it new early June), seemingly randomly (I was just opening a WMV in Quicktime), the display completely screwed up. I used Grab to take a screenshot of a sample of my screen and attached it - for some reason, part of the window (which was covered by Finder when the problem happened) stayed normal. I'm not sure what's going on but I'm guessing it's OS-related (or otherwise software) and not a problem with the display itself, since Grab notices it, too. Why does this happen, how do I prevent it, and what can I do - save restarting - if it happens again? Thanks!