Pc freezing and restating while gaming

[Disconnectcord]

I have recently build a low spec pc which I just use for grand theft 5 and battlefield 4. While I'm playing the game freezes and within 3 seconds the entire pc restarts itself. It happened twice in battlefield 4 when I crashed my jet and 3 times in GTA  when I was driving and once when there was a explosion. All parts are new besides a old ssd and power supply that I had both gave me no problems in my old pc. I can also go online and watch videos with no problem. I downloaded furmark gpu stress test and I didn't get a reboot not sure to what it can be also I didn't overclock anything

Pc specs:

 

CPU: G5400 gold
GPU: Gtx 750ti 2gb
SSD: Kingston V300 SSD 240gb 
MOBO: H310M Pro-M2 PLUS
CASE: Thermaltake versa h15
RAM: 1x8gb Corsair vengeance lpx 2400 ddr4
PSU: Cx430

OS: window 10 64bit