Computer startup problem? Check that the power button is working properly
It is something that we all fear, but it has probably happened to many of us at one time or another. We go to turn on a computer and instead of turning on, nothing happens – the computer seems completely dead. Although the cause of the problem is usually a faulty power supply, sometimes the power button may not work properly. Before you invest in a new power supply, you can easily check if this is the case.
First you need to open the computer case, this is normally achieved by removing the left side panel of the computer (viewed from the front), this usually involves removing two screws from the back of the case. After removing the panel, lay the computer on its side on a flat surface. You should look carefully for a series of thin cables coming from the front of the case towards the motherboard of the computer. The wires are normally in different colored pairs and each pair leads to 2 small pins on the motherboard; on the motherboard (and in the motherboard manual) you will find text indicating what each pair of wires does. You will have one pair for the internal speaker, one pair for the reset button, one pair for the power switch, and one pair for the power light.
The wires we are interested in are the ones marked as the power switch which is often listed as PWR-BTN or something similar. Disconnect these cables from the motherboard by gently pulling on the connector. Next, you will need a small flat bladed screwdriver which can be used to close the gap between the pins on the motherboard where the cables were connected. The computer should be plugged in and if there is a power supply switch on the back of the case, it should also be on. If the computer boots when you make a connection between the two pins with a screwdriver, then you know your problem is a bad power button or a poor connection between the power button and the motherboard. Be careful not to touch anything with the screwdriver other than these pins.
If the computer still won’t turn on, the power supply is most likely causing the problem.