LG Fusic / LX-550

I've had several power-related problems weith the Fusic. At times, the phone will randomly power itself off. There have also been times when using the AIM application that, quite literally in the middle of my entering a message, the phone will go through the power-up process when it's already on! Just the other day, it powered itself off, and when I attempted to turn it back on, I got a message I'd never seen before -- the display showed a picture of a battery with a question mark on it and said, "battery required." Not to sound like a complete idiot, but how in the blazes could the phone power on at all if the battery wasn't there?