G5 won't power up

My G5 quit abruptly and will not come back to life. Where do I begin troubleshooting?

It is a 20-inch 2004-05 model, the last unit Apple produced before going to an Intel processor (if I have those particulars right).

I apologize if this topic has been covered at length in this forum. I ran into walls trying searches that used "power" as a key term.

Any suggestions will be much appreciated. Thanks!

G'day and welcome to the forums.

As it sounds like an iMac G5 suggest you look at power supply replacement. This may alson help:-

http://jimwarholic.com/2008/11/apple-imac-g5-power-supply-issues-and.php