If your computer is similar to mine and uses an Intel GMA Driver, then this is all you have to do:
Click on: Start --> then Control Panel --> then Intel GMA Driver (or any thing that looks like it could be a color-scheme driver) --> Color (tab) --> Gamma Correction (at bottom). Gamma, Brightness, and Contrast should be options. Toggle between Desktop and Video Overlay in order to change what you see as normal, and what you see when a video or movie is playing.
Hope that helps,