Computer restarts when turned off, USB 3.0-ports stopped working etc.

[Fexan]

Hi!

I recently bought a used computer and it's been working great for a couple of months. Recently it hasn't been the same though. When i turn the PC off it restarts itself. Both when I push the powerbutton and when I turn it off in the start menu. Also all my USB 3.0-ports stopped working. I have checked, updated and restored BIOS multiple times, tried clean W10 install and clean Win8.1 install. The restarting issue is still there even when I didn't have an OS at all. Du you guys have any tips on what I should do next? Is it a hard ware fault? Is it a bad motherboard? I would love any kind of response or idea!

Processor: Intel Core i7-4820k 3,7GHz (Socket 2011)
Motherboard: Gigabyte GA-X79-UD5 (6st RAM-platser)
Grafics: ASUS ROG Radeon HD7970 3Gb Matrix Platinum
RAM: Corsair Vengeance DDR3 1600MHz 16Gb (4*4Gb)
Chassi: Cooler Master Cosmos SE
PSU: Aerocool Templarius Imperator 850W
SSD: Samsung 850 Series SSD 256Gb
HDD: WD Desktop Green 1Tb
Cooler: Cooler Master V8 GTS
DVD: ASUS RW
OS: Win8.1

Cheers!
Felix

 

[logainofhades]

I would say motherboard, or that low quality power supply, is at fault.