I have an 800 megahertz G4 running 768 ram, and 10.4, its been running slow, and now it wont even boot. When it turns on it gets to the white screen with the apple and just turns itself off. I put the OSX disk in and hold down the C key and it just locks up. I tried to boot it off the disk by holding control and it doesnt do anything, just turns off again. Any suggestions?