I have a GFCI outlet outside that just runs my fish pond pump. It has worked fine for years. Today I unplugged the pump to clean the filter. When I plugged it back in the GFCI outlet would not work. I pushed the reset button and it would not stay pushed in. I plugged something else in to the outlet to see if it was the pump that was causing the problem and it didn't work, so it is definatley the outlet. Don't understand why it would just stop working?

Everything wears out or fails eventually, even me. Sorry, but it sounds like the outlet just went bad. Not difficult to replace and not expensive. Turn power off, remove cover. Check for moisture in box or around outlet. Might try a hair drier just in case. If outlet does not reset, replace. Remove old, note which wires go where, wire new outlet exactly the same.