My iMac has been freezing for a while. Some times I'll be able to move my mouse, but I can't click anything. Other times the screen will turn a color (I've seen white, black, orange, green) with horizontal lines. I've been reading that it could be a faulty logic board, graphics card, inverter board, or a kernal panic. I've also been reading this thread on how to possibly get a free screen replacement. I was curious if any of you have experienced this and/or have any information as to what the problem may be. Thanks for your time.