I have a 2.7 Dual/ G5 Power Mac from around mid 2005.

Yesterday it was on and I returned to it some hours later to find it and the monitor off. Pressed the on button and NOTHING, no light, no fan, no beep, nothing at all.

Tried every outlet, tried reset of ram, every method....

Can I make a guess that my Power supply has died ? How difficult to replace, and how much will it cost ?