My desktop was working normally, but it sat unused for about a month while I was studying. It was covered during that time and does not appear unusually dusty. Now pressing the power button produces no response at all: no fans, LEDs, beeps, or other signs of life. The monitor turns on normally but reports no signal because the computer never starts. I have already checked the wall outlet and power cable, and I cannot see any obvious burn marks or damaged components. What should I test first to determine whether the problem is the power supply, case power button, or motherboard?
3 Answers
First check whether the power supply has a rocker switch on the back and make sure it is set to the on position. Some systems do not have an external switch, so if yours lacks one, move on to checking the internal power connections and the case power-button wiring.
A basic power-supply test using a paperclip can be an initial diagnostic step, although it only checks whether the unit starts and does not confirm that every output voltage is healthy. Disconnect the PSU from the computer first and follow a reliable pinout guide. Be especially careful with proprietary systems from manufacturers such as Dell, HP, or ASUS, since their unusual connectors may not be compatible with a standard paperclip test.
Since the machine is completely unresponsive, inspect the 24-pin motherboard connector, CPU power connector, and front-panel power-switch plug. You can also briefly bridge the two motherboard power-switch pins with a screwdriver to rule out a failed case button. If the connections are secure and there is still no response, testing with a known-good compatible PSU is safer and more conclusive than relying only on a paperclip test.
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