Microwave overheated water and screen is now blank

GE Profile JNM1851SM2SS. Manufactured May 2008. Put in a cup of cold water to heat as I do every morning. Programmed in my normal 1 min 20 secs. Opened door and nothing but steam. Cup was 3/4 full and hot. Display screen blank. Checked circuit breaker in panel (ok). Unplugged oven for a few minutes and confirmed power was at outlet. Plugged back in. Screen still blank. What could have happened? Is there a trip breaker or fuse inside? Recommendations would be greatly appreciated. Thanks in advance. QRPFUN