My computer restarts when playing games PLEASE HELP?!

[CarlSherman]

My computer has been restarting itself whenever i run games for about a year now and i dont know what the problem is, my CPU doesnt overhear and neither does my GPU so im confused??. the computer only ever shuts down when i run games. the games i run are PLAYERUNKNOWN'S BATTLEGROUNDS, CS:GO, The Forest, H1Z1. Please help, these are my specs listed below:

Graphics Card:Asus 4Gb GeForce GTX 970
Power Supply: Corsiar CX Series 750W ATX PSU
RAM: HyperX FURY Black 16Gb (2x8) DDR3 1866MHz
CPU: Intel i5-4690K,3.5GHz
Motherboard: Asus Z97-A LGA 1150
Harddrive: 1TB Seagate Barracuda 7200rmp SATA3 64Mb
Tower Cooler: Zalman CNPS10x

 

[SumTingW0ng]

What are your temperature?

 

[CarlSherman]

The teps max at 70 but usually stay around 55-66 for both cpu and gpu

 

[SumTingW0ng]

Does your PC getting enough 5V, 3V, and 12V from your power supply?

 

[CarlSherman]

I have no idea, how would i check this??

 

[SumTingW0ng]

I have no idea, how would i check this??

HWInfo64

 

[CarlSherman]

What part am i meant to look at?? to see the v