I recently bought a firewire 800 dual 1.42 GHz G4 power mac, which didn't have a hard drive or memory. I bought some memory from OWC and I threw a hard drive in it. When I press the power button I hear the startup sound however there is no video on the monitor. I'm trying to figure out whether it's a bad motherboard, video card, or if it could possibly be something else like the power supply. I have reset the PMU to no avail. Does anyone have any suggestions on what I could do to figure out which component is bad? Any help would be greatly appreciated.