I've had a similar problem, except that my clips turn bright green. Just like yours, I still have audio and such.
While trying to find a solution, my roommate discovered that my color setting were too low. She pushed them up to max, and the problem with the green screen went away. (funny that it was such a simple solution, because all the techs I talked to kept telling me ridiculous things like "install some new drivers" or "reset your system".)
I don't know if this will work for you, but it's worth a try, right?