PC booted yesterday; now it doesn't.

[calmoon]

Right. I have a computer I use everyday, mainly for gaming. The specs are as follows:

Mobo: Gigabyte GA-H61M-S2PH
CPU: i5-3330
GPU: GTX 1060 6GB
RAM: 2x4GB (8GB)
PSU: Corsair GS600 (600W)

Yesterday, after I was done with my session, I shut down the PC via the Windows start menu, as normal. Today, when I went to turn it on, nothing happened; no fans spun, no case LEDs came on... nothing. I should add that my mobo doesn't have a speaker, so no beeps either.
I thought maybe the power switch connector was loose, so I turned off the PSU, popped the case open and pushed it a bit. PSU back on, pressed the power button... still nothing. Tried shorting the pins; nothing. Tightened the RAM sticks; nothing. Took one of them out; nothing. Sounds like a PSU problem, eh? I disconnected it from everything in the system and did the paperclip test; the fan spun. The PSU was working. What the hell. After I reinstalled the PSU, and tried turning the PC on again (you never know), I noticed the power LED on my graphics card was on. With this in mind, I grabbed my phone, attached the charger cable to it and connected it to one of the rear USB ports and it started charging. This confirms the PSU's working, I guess?
It was narrowed down to either the motherboard or the CPU. I tried removing the CMOS battery for 5 minutes then reinserting it and that also did nothing. I haven't messed with the CPU and, to be honest, I don't really want to. If I have to, I'll try.

What's even happening right now? It worked fine YESTERDAY! Can anyone give me input on this? I already have a new mobo in my Amazon shopping cart, just want to make sure I'm doing the right thing before paying for it.

*Edit: I should say that my motherboard is ancient. It probably goes without saying, as it's a 1155 socket board, but I just wanted to point it out.

 

[lxgoldsmith]

there should be a "clear cmos" pin just above the front panel pins.

It's still possible that the psu is broken. You should test a known working psu with the motherboard. Unless you have experience with testing psu voltages, you can't eliminate the possibility.

You should check the vga/dvi ports on the motherboard to see if they are outputting video. If they are, then re-seat the gpu and check the drivers.

also make sure to test the other stick of memory.

It's possible that the motherboard is fried, but you should make absolutely sure that you don't need to replace the psu or the memory.

 

[calmoon]

It's still possible that the psu is broken. You should test a known working psu with the motherboard. Unless you have experience with testing psu voltages, you can't eliminate the possibility.

Thanks for the answer. I was able to get my hands on a friend's PSU to test the system. Took everything out except for one stick of RAM, the CPU, CPU cooler and case fan then plugged in the 24-pin power connector. Shorted the power switch pins and the fans started spinning... The real culprit was really the PSU, after all. New one's on the way.

Again, thank you so much for the help!