Got this problem with a month old 14" ibook G4. Sometimes it just won't start. I'll turn it on, you hear the little music, and then...blank screen. I turn it off, on again, and same thing. Also this sometimes happens when I'm away from it for a while. The screen goes blank (I don't have a screensaver set) and when I tap a key to turn it back on nothing happens. Anyone know what this is?