Computer won't boot up

[Irishsullie]

Windows 7 Home Premium
ASUS P8Z77 Pro
MSI GeForce GTX 660Ti
Intel Core i5 3570k 3.4G
PSU - http://www.topower.com/product/zu850w.html

This is currently my setup, which is recently upgraded. Everything has been working fine. Only complaint has been buzzing noise coming through the speakers while I'm gaming, and the noise changes with the graphics working harder or not. (This may have something to do with my other problem) I also apologize for the long ramble here, trying to get in as much information to you guys that may help. Hopefully.

I used it one night, the next day, it wouldn't turn on. There is a green light always on on the MB. When I try to turn it on it starts, the fans, lights and PSU fan all turn on, but then turn off. My first solution was to check the PSU. I took it out of the computer and it ran just fine by itself. Next I unplugged everything and made sure the MB was seated ok, I did that as well as check all the connections. The first thing that ended up working was resetting the CMOS by taking the battery out and putting it back in. The computer started up immediately. When I put the case back together and took it back to my room and tried turning it on, it didn't work again. I had the thought that maybe there was some contact somewhere shorting out. I'm still not sure. I rest the CMOS again and ran it on its side and everything worked fine. The next day I had it sitting upright, when I tried to turn it on, nothing would turn on, but the green light was still on on the MB. I turned off the switch on the back off the PSU and turned it back on, and it started up just fine. Since then it had worked if I would turn the switch on the PSU off and on. Now, it is back to not working again. Resetting the CMOS is not fixing the problem this time. When I take the graphics card out, the computer begins to start up, stops, then tries again, turns off, and repeats the cycle until I unplug it. There are no beeping noises and no flashing lights. When I put the graphics back in, it begins to start, all lights and fans running, but this time turns off with no cycling. Am I having a PSU issue? Is it a contact/ground somewhere? Any help would be greatly appreciated!

 

[Irishsullie]

Update on some things.

I reset the CMOS again by pulling out the battery. I also disconnected a couple cables and reconnected them, after doing so it turned back on. I've kept it running by putting it to sleep when I don't use it and it has worked fine that way. Today I accidentally turned it off instead of going to sleep and it wouldn't turn back on, back to the same start then turn off immediately.

Am I looking at a PSU issue?

I will disconnect one cable at a time and put it back together until it boots and will get back to you guys with some more information that may help to pin point something.

 

[Irishsullie]

For anyone who may be reading this looking for similar answers, I took my computer into Best Buy just so they would stick another PSU in to see if things would run. They put one in and things ran fine, though it was only connected to the MOBO, not sure if that would make any difference. Will find out then the new PSU gets here, I will let you know if that was the problem.

 

[Irishsullie]

Alright, so the issue was definitely the PSU! I ordered a new one and everything is running perfectly. I have yet to see if my buzzing noise through the speakers is still there, but maybe this hit 2 birds with 1 stone.