Computer randomly auto restart while playing League of Legend

[xzcloudzx]

My Spec:
CPU: Intel g2020
Mainboard: GA B75M-D3H
Ram : Gskill black 4Gb
VGA: HIS HD 7750 fan
PSU Corsair VS450

It not overheat, i already tested the temp while playing and it ok. it happen randomly, i think the problem is the PSU or Mainboard but i not sure, Pls help me

 

[Akashdebnath]

Your psu is of how many watt..

 

[xzcloudzx]

Your psu is of how many watt..

My PSU is 450W

 

[Akashdebnath]

Yeah i knew it ! Go and purchase a psu of 650w. That can supply a huge power to your pc.