I bought a prebuilt gaming PC roughly three to five years ago, but I don't remember most of its components. The parts I can identify are an EVGA GeForce RTX 3070 and a Gigabyte 750GM 750W power supply, part number 28200-P750G-2USR.
I put the computer to sleep before leaving for work because my room has been unusually hot. After being away for about eight hours, it would not turn on at all—there were no fans or RGB lights. On one attempt I heard a click, and the RGB briefly flickered, but nothing else happened.
Could the power supply have failed, or might another component be responsible? What should I safely test first, and is there a risk that the PSU damaged other parts?
3 Answers
Before buying parts, check the wall outlet, power strip, PSU rear switch, and the motherboard’s 24-pin and CPU power connectors. You can also briefly test the case power-switch connection by carefully shorting the two power-switch pins, but only if you’re comfortable identifying the correct pins. Given the model and symptoms, professional diagnosis or PSU replacement is safer than repeated power attempts.
You can narrow it down with a PSU tester or a properly performed paperclip test, but those tests only show that the PSU starts up; they don’t prove it is healthy under load. If you test it, disconnect it from the PC first and follow a reliable guide. Never open the PSU itself.
The power supply is the main suspect, especially given the complete lack of fans and lighting plus the click and brief flicker. Replace it with a reputable unit rather than repeatedly trying to start the PC. Hopefully it failed safely, but a bad PSU can sometimes damage the motherboard, GPU, or storage as well.
A PSU failure can also corrupt a drive or operating system, although that isn’t guaranteed. If the machine comes back after replacing the PSU, back up anything important immediately.
If the PSU passes, reconnect it and try a minimal boot with the graphics card removed, assuming the processor has integrated graphics. If it still shows no sign of life, the motherboard or power switch could be involved.