my Emerson MW1161SB microwave that is just two years old, just stopped heating. Nothing out of the ordinary has happened. I used in the morning and it worked. Tried to use at dinner, and it did not. It turns on, the tray rotates, light comes on, but does not heat. This is the SECOND Emerson micro that has broken for no reason on me in 4 years. Can you give me some ideas? What is wrong with this product?