I got my Macbook back in April/May '07 and it's been running very well and I've had no issues with it. Well today I went upstairs to check my email to find my screen had random lines running down it, the screen was garbled and the computer was frozen. I held the power button, it turned off, i hit it to turn it back on and the screen stayed blank a little while more than usual. It's odd cause that has never happened to me before and now I appear to be having a random restarting issue. I left my macbook on my desk and when i came back it was at the login screen and when i was using it earlier it restarted it self in-front of me (Never happened before). What may be causing this? I have ran the Hardware Test on my disk included with my Macbook and it seems to think nothing is wrong with it; did both one of the quick tests and one of the long tests. Should I be worried?