and you can not progam Bake or broil correct?
ok that helped ,that means you have a bad control board /clock .
Do you by chance have the model number written down somewhere?
If you open the door it will be on the face frame of the oven .
But you can`t open the door ,
That`s why I was hoping you had it written down somewhere.
OK I `m sorry to say !!
Then The only thing I can suggest Is to turn the power off to the oven .
And you will need to call for service ,with out a model number I have no idea which model you have out of several hundred Fridgidaire models over just the last few years.