I bought a prebuilt gaming PC roughly three to five years ago, but I don't remember most of its components. The graphics card is an EVGA GeForce RTX 3070, and the power supply is a Gigabyte 750GM (P/N 28200-P750G-2USR). I put the computer to sleep before leaving for work because my room has been unusually hot. After about eight hours, it would not power on at all—no fans or RGB lighting. On one attempt I heard a click, and the lights briefly flickered, but nothing else happened. Could the PSU be dead, or might another component be responsible? What should I safely test or replace next?
4 Answers
Before buying anything else, check the wall outlet, power strip, PSU rocker switch, and the motherboard’s 24-pin and CPU power connectors. If those are fine, I’d prioritize replacing the Gigabyte PSU with a quality unit of suitable wattage rather than continuing to retry the old one.
The Gigabyte P750GM has a pretty bad reputation for failing, and the click with a brief flicker definitely makes the power supply a strong suspect. Unfortunately, a failed PSU can sometimes damage other components too. I’d stop trying to power it on, replace the PSU with a reputable model, and test the system carefully afterward.
The motherboard could also be the failed part. If the PSU’s self-test works only when the motherboard power connector is disconnected, that points more toward a motherboard problem. Since the exact prebuilt model and remaining components aren’t known, a repair shop may be the safest way to identify what survived.
You can troubleshoot it by testing the PSU with a proper PSU tester or multimeter. A paperclip test only checks whether the unit starts up, not whether its voltages are safe under load, so it shouldn’t be treated as a complete diagnosis. If the PSU passes, disconnect the graphics card and unnecessary peripherals, then try starting the system with only the motherboard, CPU, one RAM stick, and the power connections.
It wasn’t an Alienware-style prebuilt, so I don’t think it has a useful model name. I’ll check the connections and look into testing or replacing the PSU first.