Q: i rented movies from iTunes and although they would start to play and have sound, there was no picture.  Mostly the screen was just bright green, although sometimes I had the pleasure of brightly coloured static and lines. Anyone know how to fix this?

Hi there, just found this advice posted by another user and it worked for me!

You'll need to do a hard reset on your computer's video card (don't worry, it's super easy!).

Shut down your computer, then hit the power button to switch it back on. As soon as you hear the startup sound, hold down the COMMAND OPTION R AND P keys all at the same time until you hear the startup sound again and release. This should fix the problem.

Good luck!

Just wanted to credit the person who gave us the solution - thanks Calancalot!

https://discussions.apple.com/message/24862914#24862914