My PC suddenly powered off while I was playing a game and watching YouTube. I discharged the PSU and reset the CMOS. After that, it powered on for only a few seconds, and on another attempt there was no display before it shut down again after a few minutes. The motherboard LED near the GPU briefly lights up, the PSU fan spins, and the CPU does not appear to be overheating. What should I check next?
1 Answer
Start by checking the motherboard’s POST or diagnostic indicators when you press the power button. Disconnect nonessential devices and try booting with only the motherboard, CPU, one RAM stick, and the power supply connected. Reseat the RAM, GPU, and both motherboard power connectors, then test each RAM stick individually and try different slots. If it still shuts off after a few seconds, the power supply, motherboard, or a short circuit could be responsible. Testing with a known-good PSU would be a useful next step.

It shut down while I was gaming and watching YouTube. I already discharged the PSU and reset CMOS. Now the PSU fan spins and the LED below the GPU briefly comes on, but the system only stays powered for about 4–5 seconds and there is no display.