I put my PowerBook to sleep and left home with it about an hour ago. I just opened it and it woke up but the screen was black. I turned it off and back on. The white screen with the apple and progress wheel came on for a normal period of time, but then the screen went all white and there were several uneven horizontal lines across the middle and froze there. I forced a restart and the same thing happened but this time I got the semi transparent window that says need to restart. I did that and I got the same screen without the message. Any knowledge, help, or suggestions would be greatly appreciated.