I've got my friend's Powerbook G4 12" 1.5GHz. She said that she left it running the other night, went to bed, then in the morning the screen was blank/black, and the fan was in overdrive. I searched many forums around the web for days trying to find similar issues and/or cure. I found some similar problems that people had, and tried a few things... I tried to reset the PMU, to no avail. I tried booting from the install disc, but it just does the same thing every time: Black screen, fast/loud fan. I've seen some responses in similar threads say that it could be a logic board issue, perhaps it's completely shot for some reason. I even (out of pure curiosity and a strange fascination for taking things apart) partially disassembled the PowerBook (using a guide from PowerbookMedic.com) to see if there was anything loose, or any connectors out, or whatever. Reassembled it, and still the same problem. Any ideas? Or does anyone want to confirm that it IS indeed a bad logic board?