PC Shutting Down Automatically When Gaming

[fuse]

So I've run into a common issue that some people run into when it comes to custom builds. Whenever I start to play, such as Battlefield 3, my PC will play for about 3 minutes then it will turn off. I've tried everything to troubleshoot everything from software and hardware. It seems as my software is perfectly fine. From the hardware perspective, I think my board might be the problem. Lately my board has beginning to have coil wine; I don't really know if that is an issue. Or my PSU might be the overall issue. 

 

My setup:

AMD P-II X4 955

Asus Crosshair IV

8 GB Corsiar DDR3-1600Mhz RAM

1x 180GB SSD and 2x 500GB HDD

2x Radeon 5770, currently only have one in the system

1250w OCZ 80P-Gold PSU

 

The PSU is overkill and the only reason why I have it is because my old system was damaged from shipping (UPS guy). 

 

I'm already planning on building a new system, but for now I still need a PC. 

[Reuben]

Your system has probably become unstable, your PSU may be creating unstable power which keeps your components from running stable.

[fuse]

Your system has probably become unstable, your PSU may be creating unstable power which keeps your components from running stable.

That what I am thinking right now, sadly I have know way of properly testing it since I don't have a spare PSU. 

[Haggis_]

I guess that you have checked the temp on the CPU and GPU when gaming

[fuse]

I guess that you have checked the temp on the CPU and GPU when gaming

Yep

[Reuben]

That what I am thinking right now, sadly I have know way of properly testing it since I don't have a spare PSU. 

Buy a new PSU, try it out, and if it doesn't help, bring it back.

[fuse]

Buy a new PSU, try it out, and if it doesn't help, bring it back.

So you think its just the PSU?

[fuse]

I've decided to put gaming and any heavy operations on hold. Thanks.