My desktop suddenly showed a green screen while I was browsing, so I shut it down. After that, it would not turn back on at all—no LEDs, fans, or other signs of power. The graphics card was replaced about a year ago, but this seems more like a power supply or motherboard problem. Is there a reliable way to determine which part failed? I can afford to replace one component, but not both. I eventually got the system working again by fully discharging it, waiting an extra minute, and then trying again. The experience also convinced me to stop plugging the desktop directly into the wall and use proper surge protection or a UPS.
4 Answers
If the PSU test passes, remove the graphics card and other nonessential components, reset the CMOS, and try booting with only the CPU, motherboard, and one memory stick installed. If it reaches a diagnostic screen, reconnect components one at a time to find what is causing the failure. A completely dead system still points first toward the PSU, motherboard, power switch, or a loose power connection.
You can test whether the PSU starts independently by disconnecting its cables from the components and bridging the correct pins on the 24-pin connector, using a PSU tester or the proper paperclip method. This only shows whether the unit can start; it does not prove the PSU is healthy under load, so be extremely careful and follow a reliable pinout guide.
For future protection, consider a UPS rather than relying only on a basic surge strip. A UPS can also help with brief power interruptions and voltage fluctuations, which a simple surge protector may not handle well.
The power supply is the better first thing to test or replace. It is usually cheaper and much easier to swap than a motherboard, and many retailers have more flexible return policies for PSUs. Before buying anything, check that the power cable and PSU switch are set correctly, then try a full discharge: unplug the computer, switch off the PSU, hold the case power button for several seconds, wait a little longer, and reconnect it.
That ended up working for me. I had to leave it discharged longer than I initially did and wait another minute before powering it back on.
I was able to get it running again, but this is useful troubleshooting advice if it happens another time.