my computer a splode

Well i have run into a bit of a problem with my computer. A couple days ago i opened it up to dust it off and tidy it up a bit. I dusted it off with one of those can of air things and reconnected several wires, especially everything from the power supply to make it at least pseudo-neat.

After reconnecting everything and attempting to boot it up it doesn't work. The cpu fan spins and the hard drive spins and all the case fans spin but nothing happens. The cpu fan doesn't slow down to a normal rate and my monitor gets no signal. I disconnected the hard drive and CD drive and got no POST.

What did i fry? what should I look into replacing? MoBo or CPU or video card? Did i do something stupid? Any other forums or sites i should praticularly look on for help? I need some help before i go into withdrawal.

I built the computer myself and it has worked fine until now so i'm decent with computers but i know there are some people on this board that know a hell of a lot more than me.