Pc shuts off randomely

[XtremeRampage]

So i built my pc a few months around two months ago and last night while i was playing a game the screen just went black but the pc was still on. I restarted it and it would turn on for a few minutes but again and went the screen went black my fans went full power.  I posted about it last night and people suggested i clear my cmos and that seemed to have fixed it but around 2 hours later it again went black and my fans went full power, then it restarted itself but the screen stayed black and the fans full power. What should i do? I have never overclocked anything. However around a week ago my power would go out randomly causing my pc to shut off abruptly so maybe that has something to do with it. I am desperate and any help,is really appreciated!

 

pc specs:

i7-7700k not overclocked

Asus strix z270e

corsair veneance 16gb ram

asus strix gtx 1080

monitor: dell u2515h

psu: evga supernova 650w g1

[TheBean]

im not sure about this but it may be that the psu is not powerfull enough.. dont quote me on that.

[Crossbred]

It's powerful enough but it might be broken. I'd get a cheapish 650w psu and test the system with that.

[XtremeRampage]

3 minutes ago, Crossbred said:

It's powerful enough but it might be broken. I'd get a cheapish 650w psu and test the system with that.

I doubt its the psu because after i cleared the cmos everything was working perfectly but after a while it started to go crazy again, leading me to believe its my motherboard

[TheBean]

2 hours ago, XtremeRampage said:

I doubt its the psu because after i cleared the cmos everything was working perfectly but after a while it started to go crazy again, leading me to believe its my motherboard

when you cleared th cmos, did you play games? what did you do after clearing cmos before is shutdown again