Trouble booting up

[kyim74]

So I recently decided to help my dad fix up his old computer. Problem is, once I connect all the cables, i turn on the power switch on the power supply, the light on the mobo lights up but when I turn on the computer, nothing happens. I double checked to make sure everything was plugged in right and there was no problem. I'm not sure of the specs since it was a generic PC bought at a local computer store. Also, the PC was working fine a couple of months ago, around last june, the last time he used it. Any ideas on what may be the problem?

 

[jackschmittusa]

What did "fix up his old computer" involve?

 

[kyim74]

Well, I guess it's not really considered "fix". Basically he just wanted to use it again but it wasn't working.