Question My PC freezes and restarts randomly and my games lag. Please help! What do I do?

[Chris48332]

I ran the Window's Memory Diagnostics and there were no problems found. I completely reset my PC that reinstall windows 10 and all my drivers. I used Event Viewer to see what was wrong and I got "The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly."
I also lag in a lot of games. Here are my PC specs:
CPU: Intel Core i7 6700k 4.00GHz
GPU: NVIDIA Geforce GTX 960
RAM: 16GB

 

[rgd1101]

make and model of the psu?
check cpu/gpu temp and usage?

 

[Fix_that_Glitch]

Do you get any warning messages when it shuts down?