Ok, My G5 will not boot all of the sudden. I start it, get the startup tone, get the white apple screen, starts the spinner and then shuts down. Yet, I can start into single user mode (says all is good, but has a weird message Error mapping module file com.apple.driver.appleintelcpupowermanagement), I can run Service Diagnostic Disk (Again all good, but strangely needed to re-calibrate thermal even though Ive not touched processors or anything. Both calibrated with no problem) and it can boot into open firmware. Yet it will not boot hard drive, my back up drive, Leopard install disc, nothing. My online researching seems to say that it is probably a power supply. I have another, but would rather not take it apart if not neccesary. Why, would a power supply cause a problem during the boot process? I thought if they went bad you would have nothing? If its bad why can I do the things that I can do? I apologize if it's a dumb question. Also, if the problem lies with the appleintelcpu thing, Why? Its PowerPc. Not Intel! Just a little confused with this and could use some clarity before I tear up my main machine. By the way, Its a 2004 G5 Dual 2.0g with 8g RAM. No problems at all until yesterday. Thanks.