I just recently started to experience some very unusual behavior on an older PowerBook G4, and I was wondering if anyone has experienced this before, as I can't seem to find any documented info on this. Basically, out of the blue, the user began to experience issues waking from sleep, while using the laptop closed with external monitor, USB keyboard and mouse. Although a powercord was always connected, the machine seemed to be powering off. For a while, hitting the power button would boot things up again, properly, but not anymore. I have since disconnected all peripherials. Now, when pressing the power button, the machine will beep 3 times and then repeat itself every so often. The sleep led will blink three times, go solid, then repeat. Sometime the harddrive tries to spin, sometimetimes not. The screen remains off. I have tried both resetting the Pmu as well as booting from cd (or any other source for that matter, both with no success. Any ideas what's going on? I figure it must be failed hardware, but can not run the hardware test from cd. Perhaps the mother board just died?