Computer freezes 20 seconds after start up, but after forced restart it works fine.

[alexander132]

This problem appeared a week ago for no apparent reason.When i start computer , when i get to the desktop, after 20 seconds or so ,it completely freezes. So i have to shut it down by pressing the power button. After that, i start it again and it works fine i don't know why this is happening. I need help cause it is getting frustrating and i don't know what to do.

Thanks in advance.

Specs :
psu : corsair 650w
gpu : nvidia gtx 980
cpu : intel 6600k
ram : 16 gb
motherboard : gigabyte g1 gaming 7-eu

Edit: This problem first appeared one day that i left my pc on and went to sleep.After ii woke up ,i found out there was a power-cut. I also have ups 480 watts.

 

[sam ginsben]

Odd, do you think it could be a power supply issue?

 

[alexander132]

Odd, do you think it could be a power supply issue?

It probably is,but i am not sure.This problem started when i left my pc on and went to sleep and when i woke up i found out there was a power-cut(i forgot to mention this in my post).But this problem disappeared for some days and appeared again.