Posted 13 October 2010 - 05:30 AM
First, you need to open the computer's case, this is normally accomplished by removing the left-hand panel of the computer.
After you remove the panel, look carefully for a series of thin wires which come from the front of the case towards the computer's motherboard. On the motherboard (and in the motherboard manual) you will find text which indicates what each pair of wires does.
The wires we are interested in are the ones marked as the power switch often shown as PWR-BTN or something similar. Unplug these wires from the motherboard by pulling gently on the connector.
Next, you will need a small flat-bladed screwdriver which can be used to bridge the gap between the pins on the motherboard where the wires were connected. The computer needs to be plugged in and if there is a switch on the power supply at the back of the case, this needs to be on as well. If the computer starts when you make a connection between the two pins with a screwdriver, then you know your problem is a faulty power button or a bad connection between the power button and the motherboard. Be careful not to touch anything with the screwdriver apart from these pins.
If the computer still doesn't turn on, then it's most likely the power supply which is causing the problem.
I hope you get what you need. Best of luck....