I've got a Powerbook G4 that has a booting issue. I will hear the startup "dong" a whirl of the drive, then it doesn't go to the grey screen with the Apple. It just sits there with a black screen. If I wait a few hours and try it, sometimes it starts up fine, or sometimes it will sit on the grey screen with the Apple symbol and do nothing. If it does boot correctly, none of the USB ports work. Any ideas on if its worth trying to repair since its 2 and a half years old and I didn't get the Apple Extended Service plan?