computer freezes and monitor loses input signal

[Mike_jo3]

Recently my PC have been having issues. I have been watching youtube videos and my computer started crashing I waited sometimes around 5-15 minutes but its still frozen the only way to fix this was hard reseting my computer (which is not good). I have hard reset it a few times just because of this problem. I also tried turning on and off the monitor when it froze but when the monitor turns back on is showed me no input signal. I think the problem lies in the video card or the connection to the monitor. I need help and opinion from you guys on how should I fix this problem.

Specs
i5-6600k
Coolermaster hyper 212x
Asus Z170 pro gaming
Corsair vengeance lpx 2x8GB
samsung m.2 ssd 256GB
ASUS GTX 970 STRIX
RM750i 80+gold

 

[R_1]

have you tried other cables? monitors?
what are the GPU temps?

 

[Mike_jo3]

have you tried other cables? monitors?
what are the GPU temps?

I have not try any other monitors as i dont have spare one.
The GPU is stable at 45 C degrees at 1-12 % Load on the core
The funny thing is it only happens when I watch my youtube.
I have not try to play games on it though since this happen