Okay, I am mildly freaked out by this... I have a G4 QuickSilver in my room that I just installed a fresh version of Tiger on last night. The computer has been off for about a day, and I am sitting on the other side of the room when it makes a "Boooooooop" tone, the power light flickered as if I had tried to boot with no/bad ram, then started up, startup chime, boots, gets to the desktop, and shuts down 2 seconds later. I have no idea why this happened. Probably unrelated, but I was messing with a 27mhz narrow band radio for my R/C car at the time this happened (and picking up interference, I am looking into that). There is a ethernet cable plugged in the back going to my Verizon Router, but there is no reason it would boot like that (I think there may be a way to boot it over a Network, but I don't know how to do that yet). I may have left my MacBook sitting on a few numeric keys on the keyboard too... These are the only things that I can think of that could of caused this. I know OSX will run scripts overnight when the computer is off, but never have seen one boot by its-self, especially if only to shut off 2 seconds later and not run a process or something. Any ideas on why this would happen? Just some strange circumstances and I want answers. 
Any Ideas? Thanks! - Billy
Any Ideas? Thanks! - Billy 