Michal_4 :
Computer turns off by itself. I reinstalled windows and it didn't help. Running an I5 4670k not overclocked. Z97x gigabyte gaming 5 mobo. (Which I think is the problem. Antec 750 watt psu. 8gb dual hyper x fury ram. Samsung ssd 250gb barracuda 1tb hdd. Gtx 970 and gtx 650 cards.
Help please.
Are you using a stock intel CPU cooler? One thing to check before ripping your hair out troubleshooting other things is to check that. I've seen so many times where one of those was incorrectly installed and the computer would shut off after a few minutes. This is normal, just the cpu/motherboard going past a thermal threshold and shutting the pc off to avoid CPU damage. Check each of the 4 posts of the cooler, everytime i've seen an issue, one of the posts wasn't in all the way.
If you go into your BIOS, go to the temp monitoring page and watch the temp while it's on. You should be anywhere from 20-40c on the cpu while in the BIOS. Anything higher that, you'd probably be seeing thermal issues with any load on the cpu.