All Fans Spinning, PC Powering up, but not starting

Hello,
I've been having this problem for a while now. Can't get to the bottom of it. I was running the PC in the afternoon just fine but it just wouldn't start when I tried it a couple of hours later. Everything seemed to work just fine. Only, my CPU Fan wouldn't spin and the monitor wouldn't turn on. I tried a few things mentioned on other forums like Resetting the GPU, and resetting the RAM. However, Nothing seemed to work. Then I tried my old Stock CPU fan which I had replaced for a bigger, custom one. This fan was spinning but the monitor problem remained the same. At my wits end, I tried replacing the CMOS Chip. The computer stopped detecting anything and only it doesn't even seem to boot. Everything powers up. The Fans all spin and the PSU seems to be working. It's just that other than the fans, there isn't any response. May I have tried something recklessly for this problem to occur? Can anyone help me figure out which part exactly has died out?



Intel Core 2 Duo E7500@2.93GHz
Transcend 4GB DDR3 RAM Module
Zotac Nvidia GTX 550ti 1GB
Windows 7 64 bit
Cooler Master 350W Power Supply