Fans and hard drive turn on but no screen or sound

Hard drive stopped working. So I followed the Step-by-Step guides on this site and replacing the hard drive. Put everything back together and turned the computer on there was nothing. No power light and no screen (black). Whats weird is some times the power light will come on and stay on. No blinking just solid.

Did some reading and found out its common for the capacitors to go bad. Took of the board and everything looked good except one capacitor looked a little bulgy. Could be the problem not sure. Put everything back together and got the same thing.

The Diagnostic LED are 1(on) 2(on) and 3 (off). From what I have read the 3rd LED is the monitor. The screen was already bad with lines so we used an external monitor but I did check the connection and everything seems good.

I can hear the fans and hard drive turn on but it does nothing. Another problem is once I do turn it on I can't turn it off. I have to unplug it. It doesn't matter how long I hold the power button it just will not turn the computer off.

Any help would be appreciated.