Look for any possible physical damage to your power supply, or any of the cords connected to it. If any damage is found, replace the power supply immediately.

Make sure the fan is working properly, and that it is not blocked in any way. If the fan is blocked or not working, try cleaning or replacing the power supply as soon as possible.

Ensure the power outlets you are plugging your PC into are supplying power to the rest of your components.

Verify that the power cords are firmly connected to the back of your PC, as well as to your power outlet.

Check that the voltage settings of your power supply are set correctly for the components in your PC.