This has happened three times to me now. I'll be working in photoshop on my powerbook and the screen will just black out. It is as if the brightness has been turned down all the way, but I have turned out all the lights in order just to barely see the screen. I make my way to the brightness settings, and theyre set to ful. I have the power cord plugged in and the powerbook has full charge. I know this is not an overheating issue because I had just started working on my computer for less than 20 minutes when it happened this time... whats going on?