hey mate,
try having a look at you Nvidia settings because i had a simular broblem a while back. (colour seemed to be weird when i was playing any sort of video on the computer)
right click on the desktop and go to Nvidia control panel. there sould be an "adjust video colour settings" make sure these are set to defaults by clicking "restore to defaults" in the top right hand corner. then click appy.
if this doesn't work it could be because of a the video codec your using.. however if you haven't installed a new one lately then it wont be.
good luck!
Triston
May 2008