I just picked up a Power Mac G5 yesterday (traded two 2nd Gen iPod Touches for it) and it worked wonderfully. 4gb of RAM, 500 GB hard drive. Early 05 Model I believe. I used it for the rest of the evening and then unplugged it and took a look inside. I took out one of the RAM cards to see what kind of RAM it was and then put the card back in. From this point on the computer will not boot, shows only the black screen, and fans are on full blast. I feel like I have to reset something with the keyboard, but don't know exactly how or what. Any help is appreciated.