Your computer's power supply may have nothing wrong with it, even if your computer does not seem to have power.
Some older computer power supplies, especially those manufactured by Gateway, have a "test switch" installed. This is intended for troubleshooting, when a user is trying to figure out whether a problem with his computer's power is a problem with the power supply itself.
Power Problems
If you try to turn on your computer and nothing happens, your first instinct is probably to think that it's "dead." But there are a lot of things that could be wrong with it, and the test switch helps an engineer narrow this down.
Using the Test Switch
Before using the test switch, the power supply should be disconnected from the motherboard and from all drives except for the primary hard drive or optical drive. When the test switch is pressed, the power supply may or may not come on (an LED will light up and the fan will begin to spin.)
What This Means
If the disconnected power supply comes on when the test button is pressed--but not when it is connected to all computer components and the computer's power switch is pressed--the problem is not with the supply itself but with another computer component, such as one of the connectors or the power switch itself. The test switch helps you rule out a major possibility when diagnosing your computer's problem.
Tags: test switch, computer power, power supply, problem with, power switch, supply itself