We cooked a turkey with our friends on thanksgiving and came across this weird stove problem just when we needed to flip the bird.
Alanna figured it out. It seems that the actual lock of the stove (do they have locks?) had gotten stuck or changed. We just had to open up the front door and turn the small piece of metal on the inside top of the stove until the beeping went away. Crisis averted.
And there was much rejoicing and turkey. My wife is smart.