PC does not post and cannot turn off

[Nooby_]

Hey, so I came home today and my PC is not working.
Specs;
CPU: AMD FX-9590
GPU: GTX 970
Motherboard: Gigabyte 990fxa-ud3 r5

When I turn it on all the light in the case work, but none of the peripherals will turn on, including no display what so ever on the screen. Using the power and reset buttons do nothing and I am forced to cut off the power with the switch on the back to turn it off because it will usually just sit there forever. Occasionally, it will power on and 10 seconds later will turn itself off. I am unsure what is wrong, all I could think of to do was clean it out and try reseating the GPU and RAM and try replugging in different power cables and such. Thanks for the help to anyone that can

 

[rgd1101]

make and model of the psu?

 

[Nooby_]

Power Co Ltd. ATA-800FB-B

 

[jason201]

Power Co Ltd. ATA-800FB-B

That's a cheap PSU of questionable quality, and judging by the issue, I'd say there's a strong possibility it's the cause.
However, it could also be some kind of problem with your case's power/reset buttons (to make sure, I'd suggest you disconnect the power/reset wires from the motherboard's front panel header, and turn the computer on by touching the specific 2 power pins on the board with a flat headed screwdriver

 

[Nooby_]

Jumping it produced the same result sadly

 

[jason201]

Then I'd say you should definitely get a new PSU.
A 650-700w one do fine (as long as of a reputable brand, such as Seasonic/Evga/Corsair/Antec)