How do I unlock the oven door when self-clean has not functioned?This is a 30-inch 22-year-old slide-in electric range. I cannot access the model number siince I cannot open the door. I tried to begin a self-cleaning cycle, closing the door and manually activating the lock, but after puching the correct buttons to begin the cycle, nothing ever happened...no heat and no indicator lights e ver came on. Now I am unable to unlock the oven door.