Screwed up video playback

Whenever I try to play video on my computer, it is always extremely dark and slightly green tinted. Everything else looks fine, it’s just the video always looks off. I can sometimes fix it by pausing it, switching windows for a second or two and coming back to the video, but that usually doesn’t fix it for long. Is this a common problem, and is there any way I can fix it short of getting a new video card?

(I’m using a GeForce MX420 on Windows XP Pro. All the latest drivers are installed.)

Well I seem to have fixed it by tweaking some DirectX settings.