GE Self cleaning Gas oven "start" button won't work

We have a GE Self Cleaning Gas Oven that we are having problems with. The "start" button on the top front panel will not start when you press it. You can put the temperture in, then press start & it will not activate.

 

Sounds digital controlled. Have you tried to maybe reset it by turning off the circuit breaker and let it reset and try again? Or can you press "clear" and try again? Does any code come up after it does not start? How do you normally know with this stove that it has started after you press start? Like, what comes up on the screen, and when, after you press start? I am trying to figure out if the stove has brains to know say if it lost ignition, gas supply or whatever, and will not allow the start procedure to progress. But you'd think there would be say an F code, that would come up on the screen, regarding this.