Ok, lately I've been afraid to let my Mac fall asleep because it begins to act up. When I wake my computer up by pressing a button on the keyboard of clicking the mouse one of the three things below will happen: 1. Computer will be slow for about 5 mins. 2. The screen will stay black and I have to pound on the keyboard to wake it up. 3. The computer wakes up but the display stays black and after a few seconds the fans begin to turn at about 500MPH and sounds like the computer is about to explode. Why is this happening? How can I stop it from happening?