Computer Restart Loop

[Patflute]

Restart loop - My computer restarts itself after about 3 seconds with no visual displayed.

A few weeks ago my computer starting doing the restart loop. I reseated the RAM, but that didn't help. I realized that I OCed my GPU, so I removed the GPU and the computer started up. I removed the OC software and readded the GPU and the computer worked fine for 2 weeks.

Today my computer froze with no programs open, I restarted and I got the restart loop again! I removed the GPU and it worked after looping only once. So I put the GPU back in and it worked, then restarted itself while in Windows (only a few seconds into being in Windows). I removed it a second time and now I get the restart loop without the GPU.

I did not overclock again after the first incident. I did not do anything new in the last couple days to warrant this.

What exactly is the problem and how do I fix it?

My specs:
CPU - i5-3450
GPU - Gigabyte Geforce GTX 660 OC
Case - Cooler Master Elite 430
RAM - Patriot Viper II Sector 5 8gb (2x4gb) DDR3 @1333mhz
Motherboard - Gigabyte H77 mATX
Power Supply - NZXT HALE82 650w Modular 80 Plus Bronze
Storage - Momentus XT 500gb, Hybrid HDD/SSD.
OS - Windows 8.1 Professional
Monitor - Benq GW2250
Mouse - CM Storm Inferno
Keyboard - Steelseries 6Gv2

 

[bigboxes]

My first guess would be the power supply. Try swapping out with known working PSU. Next, I would suspect the memory. Try just one stick and move the ram to different slots. Run memtest86 and see if you get any errors. Try swapping out memory with known working ram. Outside of that you may have a bad mobo. Happy troubleshooting!

 

[Patflute]

FIXED IT - When I reseated the RAM in the first instance of the problem I ended up not reseating it probably. So basically I caused another restart problem by fixing my previous. Life.