PC Won't power on

[leoscott]

I have an I7-4790 system that had been running fine for 2 years. 2 days ago I went to eat dinner and when I came back it was off and it won't power on. I have tried:
1) replace power cord with another power cord and plugged into a verified working outlet
2) replace the Corsair AX860 PSU
3 replace the main board
4) checked the power switch at the motherboard connector with a multimeter
5) shorted the motherboard power switch pins with a screwdriver
So far none of those things has given any sign of power in the machine.
Any suggestions?

 

[clarkjd]

I have an I7-4790 system that had been running fine for 2 years. 2 days ago I went to eat dinner and when I came back it was off and it won't power on. I have tried:
1) replace power cord with another power cord and plugged into a verified working outlet
2) replace the Corsair AX860 PSU
3 replace the main board
4) checked the power switch at the motherboard connector with a multimeter
5) shorted the motherboard power switch pins with a screwdriver
So far none of those things has given any sign of power in the machine.
Any suggestions?

Since you replaced the MoBo, I am going to refer you to the general troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems
Work through the list. WORK!, not just read!
If you still have issues, come back here with the results of working EACH step in the list. Since we can neither see nor touch your PC, the results of each step gives us valuable information and helps us eliminate possible errors, allowing us to give you a reasoned diagnosis. help us to help you!

 

[leoscott]

I now think it's the EVGA GTX 980 video card. I had forgotten that when the PSU goes into a fault mode, overcurrent, you have to unplug it and let it drain before it will restart. I basically unplugged everything but the CPU and let the PSU drain and the MB powered up. I then started plugging things back in, fans first. Then memory sticks, then SATA power. It started every time. Finally when I plugged in the 980 it wouldn't start. I removed the card and let the PSU drain and it would again start.