Question My pc restarted itself

[Sunsetflare017]

I was playing arma 3 for like 2 hours after I was done I just closed the game and set there then the pc just restarted randomly turned off and on I dont know why can anyone help?

 

[rgd1101]

full system spec? include make and model of the psu

so the pc doesn't work/boot anymore?

 

[Sunsetflare017]

Specs:
Operating System: Windows 7 Ultimate 64-bit SP1
CPU: Intel Core i5 4570 @ 3.20GHz
RAM:16.0GB Dual-Channel DDR3
Video card: NVIDIA GeForce GTX 750 Ti
My PSU: I think its 550 Walts dont really know how to look for the model and make
the pc is working now I was just getting worried its going to be a problem, so far it only happend with ARMA 3
like I finished playing for like 2 hours closed the game and like 10-15 min after the pc just randomly restarted.
didnt happen to any other game and so far didnt happen again