I have a problem with my ibook that I think may be due to a power fluctuation. My power adaptor cord got a little frayed and I had wrapped a piece of electrical tape around it while waiting for a new one in the mail. I came in from lunch a few days later and found the computer off. I was unable to get it to start. I tired a friends cord and it worked just fine for several hours, ran the hardware test disk and everything passed (logic board, display, etc) But after shutting it down I've been unable to get it going again (using new cord). I hear the start-up tone and a short whirring like its about to go, but no screen comes up. I'd appreciate any advice, I'm dying here! Should I reset the Power Manager?