[Troubleshooting] Cleaning my Rig Gone Wrong

So my rig that I built about 3 years ago was acting weird when I was playing BF3 (meaning it was shutting off for no reason). This was the only game that I was having the issue with, Batman Arkham City and Assassin's Creed: Revelations didn't have any issues. Thinking that it could be my CPU running a little hot, I unplugged my rig, opened it up and removed the CPU heatsink so that I could clean it better. While I was in there, I pulled out my GPU and took a can of air to that too. I then reseated the GPU and heatsink and went to boot back up. As soon as I started to log into Windows, my computer shut down. I then tried booting up once again, but received an error message in the BIOS POST that hadn't been there before saying that there was some issue with my memory timings and that I should reset them to default in the CMOS. This was a little weird since I hadn't touched the RAM, yet I tried reseting the CMOS jumpers (my mobo has jumpers for some odd reason, lol). This time, the POST seemed to go successfully until it started to do the inital Windows load animation (before the login screen) then it shut off again. I tried booting with just 1 stick of RAM (I'm running 2x2gb sticks) just the other stick and still no luck. I even tried reseating my CPU for some odd reason, and no luck. The other odd thing is that my mobo has a small 2 character display directly on it that shows different codes during POST, and every time it has reached FF meaning fully functional, so the POST is going successfully. Didn't know if anyone had any suggestions, unfortunately I don't have access to any spare parts at the moment, so I'm trying to work with what I have. Here are my specs:

Mobo: EVGA 780i SLI CPU: Intel E8400 dual core 3.0 GHz GPU: nvidia 9800 GTX+ Black Edition (means XFX factory OC'ed it) RAM: 2x2gb Corsair DDR2 800 Mhz Hard Drive 1: Corsair SSD 128GB Hard Drive 2: Western Digital 1TB PSU: 750w PC Power & Cooling

Any help or suggestions would be greatly appreciated!