It’s something we all dread, but has probably happened to many of us at one time or another. We go to turn a computer on, and instead of sparking into life, nothing happens — the computer appears completely dead. Though the cause of the problem is often a faulty power supply, sometimes the power button itself may not be working properly. Before investing in a new power supply, you can quite easily check to see if this is the case.
First, you need to open the computer’s case, this is normally accomplished by removing the left-hand panel of the computer (when viewed from the front), this generally simply involves removing two screws from the back of the case. After you remove the panel, lay the computer down on its side on a flat surface. You need to look carefully for a series of thin wires which come from the front of the case towards the computer’s motherboard. The wires are normally in different coloured pairs and each pair leads to 2 small pins on the motherboard; on the motherboard (and in the motherboard manual) you will find text which indicates what each pair of wires does. You will have a pair for the internal speaker, a pair for the reset button, a pair for the power switch, and a pair for the power light.
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.