Hmm. sounds very familiar. I had the exact same problem and the Apple store I took it to, apart from losing my iBook for three weeks in their internal system, claimed it needed a whole new motherboard! Turned out, according to their techies, that the power part of the motherboard was up a certain creek and could not be fixed. 800 euro later, grrr, I got it back and it has worked fine since. I still use my auld iBook as it is sooo portable compared to the new MacBook Pro I just bought. I can flip it open anywheres, whereas my Pro cannot be opened in a cattle-class seat for a bit of movie watchage on-plane. [Not that you can do that anymore anyways]. [But it is way better than my tiny TV for watching movies at home!] I hope that your problem is different and the solution is affordable. All the best, enjoy SF CK