I checked for the reasons there was no power to the microwave. Then I talked with the technician at AppliancePartsPros who stated that it was most likely a blown or defective fuse. My LG microwave has two thermal fuses, a fuse assembly with two prongs and a short (1 inch) barrel type fuse. I replaced all of them after viewing YouTube videos and then reviewing the diagram for my microwave on the AppliancePartsPrps website. That was very helpful in locating where the fuses were installed.
It took me longer than it should have, (I am not very handy at some things), but with the help of the AppliancePartsPros website, the technician and You tube, I was successful.