Need help with PC turning off on its own

sorry if this is the wrong forum.
recently I have had power issues with my pc. what happens is when I start up a game I will get to play it for 5 - 10 minutes maybe and it will shut off on its own. I checked on all of my plugins and they seem to be fine. I haven't overclocked my pc so I don't think that it is that and I bought a psu that was over 100 kw more than the required for my pc. if you know what could be causing this please help. thank you!

all right here they are.
[PCPartPicker part list](http://pcpartpicker.com/p/1d2Oy) / [Price breakdown by merchant](http://pcpartpicker.com/p/1d2Oy/by_merchant/) / [Benchmarks](http://pcpartpicker.com/p/1d2Oy/benchmarks/)

Type|Item|Price
:----|:----|:----
**CPU** | [AMD FX-8350 4.0GHz 8-Core Processor](http://pcpartpicker.com/part/amd-cpu-fd8350frhkbox) | $179.99 @ Microcenter
**CPU Cooler** | [Cooler Master V8 69.7 CFM Rifle Bearing CPU Cooler](http://pcpartpicker.com/part/cooler-master-cpu-cooler-rruv8xbu1gp) | $47.99 @ Newegg
**Motherboard** | [Asus Crosshair V Formula-Z ATX AM3+ Motherboard](http://pcpartpicker.com/part/asus-motherboard-crosshairvformulaz) | $214.99 @ Amazon
**Memory** | [Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory](http://pcpartpicker.com/part/corsair-memory-cml8gx3m2a1600c9) | $71.37 @ Amazon
**Storage** | [Sandisk ReadyCache 32GB 2.5" Solid State Disk](http://pcpartpicker.com/part/sandisk-internal-hard-drive-sdssdrc032gg26) | $39.99 @ Microcenter
**Storage** | [Seagate SV35.5 2TB 3.5" 7200RPM Internal Hard Drive](http://pcpartpicker.com/part/seagate-internal-hard-drive-st2000vx000) | $99.99 @ NCIX US
**Video Card** | [Asus GeForce GTX 680 2GB Video Card](http://pcpartpicker.com/part/asus-video-card-gtx680dc2o2gd5) | $408.98 @ SuperBiiz
**Case** | [BitFenix Colossus Window (White) ATX Full Tower Case](http://pcpartpicker.com/part/bitfenix-case-bfccls500wwwb1rp) | $152.61 @ NCIX US
**Power Supply** | [Enermax 550W 80 PLUS Bronze Certified ATX12V Power Supply](http://pcpartpicker.com/part/enermax-power-supply-b550sa) | $79.72 @ Mac Mall
**Optical Drive** | [LG GH24NS95 DVD/CD Writer](http://pcpartpicker.com/part/lg-optical-drive-gh24ns95) | $15.98 @ Outlet PC
**Operating System** | [Microsoft Windows 8 (OEM) (64-bit)](http://pcpartpicker.com/part/microsoft-os-wn700404) | $89.74 @ Amazon
| | **Total**
| Prices include shipping, taxes, and discounts when available. | $1401.35
| Generated by PCPartPicker 2013-07-24 01:13 EDT-0400 |

thanks I will buy a larger psu but the main problem that I have with that idea is that on pcpartpicker it says I only need a 450w psu .