Microwave stopped working completely The screen on the side shows F3

Hi Michael,

Without more specific information (i.e., the model number as requested by @jayeff) all we can really do is give you generic information. For most GE microwaves, the F3 error code indicates a problem with the keypad. Usually that means replacing it, but there are certainly things you can try first, such as resetting the microwave, unplugging it and cleaning the membrane keypad. Here's a page from Register Appliance Service describing the issue and a few possible solutions.

GE Microwave F3 Error Code: How to Fix It - Register Appliance Service