So, I just had a weird random shutdown about 20 minutes ago. I rebooted the machine twice and everything was working fine after that, but I checked Console to see if anything was wrong. Console reported "05/03/2010 14:12:37 kernel ApplePMU:MU forced shutdown, cause = -127" and a little later, "Improper shutdown detected!" I don't know what's going on here, although I suspect that the PMU might be acting weird because the battery is dead. No kernel panics are showing up in the console log, and I didn't get the "Mac OS X recovered from an unexpected shutdown" message on reboot. I'm hoping to God it's just the dead battery and not a failing logic board or something. I haven't seen any of the symptoms of that, though; as I said, I did two test reboots after the computer shut itself down and everything seems to be fine. Specs: the computer is an iBook G4 1.2 ghz, early 2004 model. It's been in good working order except for a dead battery.