When I try to boot up I just get the power symbol with the warning to push the power button and restart the computer. If I try to boot to a dvd it gets farther but still gives the same errors. Any ideas on how to fix this? Only change is I updated to 10.4.2. PB aluminum 15" 1.33 ghz g4. I vaguely remember pram but don't even know if it still applies to new macs. 