Loss of Video Signal on Startup

So I just finished up installing new RAM, a new CPU Cooler, and a new GPU Cooler... My computer booted right up no issues, until it lost video signal right after I saw my password screen. My computer was still on, and (to the touch) nothing was overheating... So I rebooted, same issue..

I then booted in Safe Mode, which booted right up. I backed up all my files and whatnot onto a secondary HDD and proceeded to reinstall Windows 7, thinking that would fix the issue, and I was sadly wrong.

I then booted back into Safe Mode, in which my computer ran fine, reinstalled all the drivers, and proceeded to restart my comp. The same thing happened, lost video signal right when my password screen showed up.

I am all out of options here, honestly. I thought it was because I normally use two monitors but only boot on one now, but that wasn't it. removed the new RAM and that didn't work, thought my comp was trying to run off an On-board card, but that wasn't it(computer only recognizing my GTX 550).

This is rather obnoxious.

Thanks for the help.