Some of this is related, some isn't. I have a PMG5 dual 2.0GHz that had been showing some signs of flakiness so I bought a MacPro and decided to shelve the G5 until I could focus on it. The flakiness was the fact than the FireWire on the front stopped working, then the USB on the front stopped. I bought a FireWire PCI card with three ports on it, they all worked, then two died. I was told that this model of G5 was known for degenerative motherboard issues and that the fix was to swap out the whole motherboard. I let it limp along until I could rely on it anymore. After a few months of non-use I decided to try and fire it up. When I push the power button on the front the white light comes on and there is a "click" sound from the power supply, and that's it. I took the side panel off to see if I could see anything. Again, I push the power button, the white like comes on (and stays on as long as I hold it in), all of the fans twitch for a moment, there is the click sound, and then nothing. With all of the other problems attributed to the motherboard I could accept that that's the problem. But it acts like its a power supply problem. BTW, the same "click" sound is heard when you plug the power cord into the wall. So before the button even gets pushed it's making this clicking sound. Any ideas? Also, I had to remove the hard drive to rescue another machine so it has no HD in it. Does the PMG5 require that a hard drive be in the box before it will even power on? Thanks in advance.