Try resetting it, here's how:
Press the “Off/Clear’ button to cancel anything on the display, and reset the microwave. This is a soft reset and will simply get you out of any program you have started. Press it when the cooking complete reminder appears on the display, for example, and the “Your Food is Ready" message will disappear.
Press the “Off/Clear’ button for three seconds to turn the “Control Locked” child lock off.
Reset the cooking program if “Off/Clear” was pressed accidentally. For example, press the “Defrost” button again, and turn the dial to select the defrost time you want again. Press "Start."
Perform a hard reset. Pull the plug out of the wall power supply, and wait a moment. Plug the GE microwave back into the wall power supply to reset any anomalies with the microwave’s memory. You will need to reset the time of day if you perform a hard reset.
Reset the time of day. Press the “Clock” button, and turn the dial to set the hours. Press the dial to enter. Follow the same procedure for the minutes and a.m. or p.m. Press the “Start” button to start the clock.