I will start this story from the beginning. My buddy gave me his pc to work on with the issues being it will no longer turn on. You push the power button and nothing happens. 1st I bench tested his PSU and it worked properly. Just to make sure I installed a known good PSU and still would not fire up. I swapped out all of his RAM with known good RAM. Still nothing, I even went as far as to swap CPU's and again still nothing. At this point I had decided on a Mobo issue as he has stated it had overheated in the past.
So I order him a new old mobo. Swap it all in and the issue still remains the same. At this point I realize I had overlooked the fact that it had a aftermarket GPU. I removed it and PC fired right up. He had a 9800GT and it was pretty scorched once pulled apart. I plugged a monitor directly to the board and recieved no signal to the monitor. I installed a known good GPU into the board and used that and still no signal going to the monitor. (light never turns green)
At this point I figure I am either clearly looking over something or the issue is just beyond my grasp. Either way it is frustrating. I will appreciate any attempt at a response if it leads me the right way.
Mobo - Asus M4A77
PSU - OCZ 500w also tested silverstone 500w
CPU - AMD Athlon II x2
RAM - Corsair 1gb x 4 also tested Ballistix 2gb x 2 DDR2
HDD - (1) 500gb Seagate (2) 50gb Seagate
GPU - 8500GT also tested a GTS250