Computer shutting off when I play games

[eprocks6054]

Ever since recently when I run intensive games such as bf3 and planetisde 2, as soon as it launches and I join a game my computer instantly turns off. I think it is the motherboard telling the psu to shut off because its glitched but I am not sure. It also could be the power supply though, but when I leave the computer on, I can keep it on as long as I want and it won't shut off. All the games I play I can run maxed out and have done so in the past so this is odd. A while back I had a water leak a little on my motherboard from a heatsink cooler leak when I took it off but I quickly got it off, so I am not sure if something with the motherboard is messing up. It would be appreciated if someone could help me solve this issue.
Specs:
CPU: fx - 8350
GPU gtx 660 ti
MOBO: 970- A- D3
PSU: 700 watt

 

[knightdog56]

Please list make and model of power supply. Also what revision # of motherboard.