I can't get your model number to come up. Are you sure that is the correct number?
If this is like all the other GE ovens with a simmilar model number, 98% of the time this problem is due to a bad electronic oven controler. Its a very common issue with them.
Check your power supply first to be sure you don't have a bad connection with one of the power wires or the nuteral, and if all that looks OK replace the clock. Since I can't get your model number to come up I can't say for sure, but a lot of these clocks are discontinued in which case you will have to have the part repaired.