Powermac G5 Dual 2.5 wont start up? Went through all I can think of. Help!

Question

I have a Power Mac G5 Dual 2.5ghz with 8gb of Ram and two 1tb Hitachi Harddrives.
My PCI Cards exist of a 256mb Graphics Card, a 128mb graphics card, and a Esata 4 Port card.
My computer was perfectly fine when I left for work in the morning.
I got back and my monitor light was on but my computer wasn't.
Which is odd because I have it automatically reboot when it shuts down from a power failure.
Tried the button and it didn't work.
No light comes on over the button on the tower.
So I thought the powerstripe faulted.
Went back to reset it.
Nothing.
Then switch the outlets.
Nothing.
Switched the power cable.
Nothing.
Opened it up and reset the SMU/PMU.
Nothing.
Took all the ram out and switched them around in the one spot.
Nothing. (if it was the ram atleast one pair of the 8gb should be fine and nothing)
Someone mentioned replacing the PRAM Battery? (going to try that tommorrow)
Any Idea if thats viable?
Or do you have any other recommendations?
It isn't under warrenty anymore.
So anything that might work that will save me from technical support from apple witll be helpful.
THANKS.

Answer 1

No - No Click.
It is like unresponsive.
As f there was no juice going to it at all.
But I know there is.
A friend told me its probably one of two things.
Both are bad.
One is the power supply is shot. (sadly as expensive this would be I am hoping it is this)
Two is the motherboard is fried. (which is probably the worst thing that I could think this could be)
No matter what is I have no warranty so that means any work will cost money as well as parts.
If it costs more then $500 I am going to take my two 1TB drives and sell the ram and the rest for parts.