Yu dont say what codec is givign the green screen, but try different renderers and also turning off hardware acceleration in the codec settings.
For example. If I'm using the enhanced or VMR9 renderers and Hardware accel is ON, I get a green screen with my ATI drivers. But VMR7 and H/W accel ON works.
If you right-click on the green screen while video is playing back and select Directshow Filters and then your video codec there is probably an acceleration option there.
May not help, but worth a try....
Richard