Power Button does nothing

Does anyone have experience of this?

I have a G5 tower from 2004 that won't turn on. When its plugged in it makes the clicking noise but pressing the button does nothing (no light, no fan)

This also happened a few days ago so I opened it up and reset the PMU and it worked fine but that doesn't seem to be working this time.

I will get apple to look at it this week but would be grateful to know if anyone on the board has experience of this and knows what the problem could be.

Welcome to the Forums Barry.

Sounds like you have a failed power supply, however have you tried changing the PRAM battery, leaving it unplugged overnight, and then booting?

Does it do the chime? As in does the computer start running at all? cause i have a similar problem to that on my powermac g5 duel. It starts up but theres no sound no nothing.... and only 1 processor runs. If you have that problem... then it COULD be the power supply and also it could be your logic board...