New cpu fan, no video

Up until this point, my home built computer was working perfectly. I decided that I wanted to put a better CPU cooling fan in so that I could OC my CPU. Anyways, I turned my computer off, unplugged it, and opened it up. I grounded myself, removed the old CPU fan, and installed the new one. After I put the case back on, and plugged the computer back in, it stopped working properly. It powers up, all fans working, but no video signal can be seen through the monitor. Any thoughts or suggestions?

Also, I am getting 1 long beep followed by 2 short beeps when the computer starts up. (Which from what I recall, is what always happened when the computer booted up, but I could be wrong.)

XFX nForce 750i Extreme Edition Mobo
BFG Tech 9800GTX+ Video Card
Q9400 Intel Core 2 Quad CPU 2.66 GHz
OCZ SLI 4096MB PC6400 DDR2 RAM

well i had read that list about a month ago when i originally built the computer. i'll double check everything tho.

You might want to post what the problem was for people with similar issues.