i've had to do a hard restart 3 times so far and each time was weird. The first time a shadow covered my screen like a curtain being closed in Bladerunner - Mac OSX had unexpectedly quit. Not firefox, not another app, MAC OSX. The second time I was watching Weeds and out of nowhere my monitor turned into a mood ring, literally...like someone put my laptop in an MRI machine. The thir time out of nowhere this crazy fuzz like on TV but with colors took over the screen.
Each time I:
1) held down the powerer button down for about 5-7 seconds to manually shut down (aka hard reset)
2) after botting up everything was fine
3) All I remember doing was clicking while in fullscreen, maybe too much. I'd recommend not clicking a Divx movie when it's in full screen at all.
BUT!
I had the same problems with Divx on Stage6. it has nothing to do with ninjavideo.