Power Mac G5 Won't Power on or Off?

I thought I would check here to see if there may be a simple fix before I take my Power Mac G5 in.

I was editing some video and took a break for some dinner. I know the machine was in sleep mode at the time, storm knocked power out. I have the machine plugged into a Monster Surge protector. When the power came back on (oddly) the LED power light on the front was on again like the machine was still in sleep mode.

That is all you get now. I tried to hold in the power button to hard reboot (nothing). If you unplug it (wait) and plug it in again, you hear like a metalic "clink" and the LED power light comes on but that is where it stops. I also tried just plugging it into the wall by-passing the surge unit and the results are the same. It seems to power on according to the light without depressing the power button but seems to be in sleep mode, then again I have no idea...

Got it figured out. Thought I would post the fix incase someone else runs into this problem. It would appear that it was a simple fix. Needed to replace the internal battery. The little 3.6v battery must have something to do with the G5 powering up. Stuck a new battery in it and all is fine now...

Reads like a PSU problem, possibly an internal fuse has gone. As I understand it, the indicator LED powers on before anything else. Do you hear the hard drive spin (a high-pitched whining noise), followed by the slight scratching noise commonly associated with the HD being read, plus fan noise; or is there complete silence after the 'clink' you refer to?

Edit: ignore the above, glad your power issue is resolved.