Why Does My Desktop PC Suddenly Power Off Without Warning?

A sudden hard power-off is commonly caused by overheating or a power-delivery problem. Monitor CPU and GPU temperatures with a hardware monitor while gaming or doing other demanding tasks, then check whether the temperatures spike right before the shutdown. Also inspect the CPU cooler, make sure its fan or pump is working, and clean dust from the heatsinks and case airflow paths. Thermal paste is worth checking too, but don’t assume it’s the only possible cause.

Give the inside of the case a thorough cleaning, especially the CPU cooler, graphics card heatsink, intake filters, and exhaust fans. Shut the PC down, unplug it, take it somewhere ventilated, and use compressed air to blow the dust out while holding the fans still. Also confirm that every fan spins normally when the system is running.

Look in Event Viewer under Windows Logs > System after the next failure. A Kernel-Power event may only confirm that the computer lost power unexpectedly, so it won’t necessarily identify the cause, but nearby warnings or hardware errors can provide clues. Checking temperatures at the same time should help separate an overheating shutdown from a PSU or motherboard problem.

Check the power supply model and wattage before replacing anything. You can usually find that information on the PSU’s label or the system’s build paperwork. The RX 6650 XT and Ryzen 7 7700X don’t automatically require a 1000-watt unit, but an old, low-quality, or failing PSU can still cause an instant blackout. If temperatures look normal, testing with a known-good PSU would be a useful next step.