I am a first-time PC builder and started my project a year ago after I purchased your guide to building a dream PC. I have been collecting my parts over the past year and finally got a chance to piece them all together. The problem? My computer won’t start! I get a green LED on the motherboard when I turn on the power supply, but nothing happens when I push the case’s power button. Nothing starts: no case fans, no power-supply fan, no CPU, no videocards.
What’s going on?
If the machine still doesn’t start, try directly shorting the two pins to POST the board—use the tip of a screwdriver to temporarily bridge the two. This will eliminate a bad power switch or wire on the case as a culprit. Also, make sure that the ATX12V and 24-pin main power connector are firmly inserted. If you still don’t have any luck, try removing devices from the board one by one (make sure you power down the PSU first).
After each removal, try restarting the machine. You might even have to unplug the hard-drive power cables from the board. Sometimes a pin in the power connector will get shorted against another, which can cause the PSU to immediately turn off.
Front-panel connectors are often mislabeled or don’t
color-match the appropriate wire, so refer to your motherboard
manual to determine which connector is which.