Pc power on ut not turn on

Hello,

I've had my desktop computer for about one year now. It is an Acer Aspire E380. On Saturday afternoon, it was going a bit slow so I decided to restart it. However, once it turned off, it will no longer turn on and boot up.
The power button usually lights up, but now it does not. But, the decorative words "Aspire" at the bottom of the tower still lights up. The DVD drive still opens, and a few lights blink on start up as usual.
The screen is blank. All of the fans seem to go, except for one. It is the one in the center of the computer on top of a group of metal prongs. It spins upon power up but stops. The power supply fan runs, the other fan runs too.
I have made sure everything is plugged in, and tried plugging it into different outlets. I can't boot from a CD, the keyboard doesn't turn on and neither does the mouse.
As far as starting up goes, everything sounds normal. No beeps or clicks to hint at harddrive failure. Sometimes when I try to start it up nothing comes on but the center fan on the metal prongs (the one that would run for only a few seconds) goes on full blast until I turn it off.
If everything seems to be going, what is stopping it from booting up?