Gas ovens generally stop heating because of a lack of fuel, ignition problems or a blockage in the burner tube. With electric ovens, the most common problem is a burned-out heating element.
To check the fuel supply on a gas stove, owners should turn on the heat for the surface burners. If they light and burn normally, gas is available. If they do not burn, propane users may be out of fuel. Natural gas users should contact the utility supplier for more information.
Many gas systems have interlocks that check for the heat of a pilot light. If there is no heat, they disable the gas feed to prevent further problems. If gas is available and the pilot light is functioning, the problem is sometimes a blockage in the burner tube that prevents the flames spreading through the unit.
With electric stoves, owners are usually aware of power outages before turning on the oven. Heating elements are subject to high heat and after several years of service sometimes burn out so they no longer conduct electricity. A multimeter set to show resistance that reads infinity is a sign the oven element is bad. Kenmore replacement elements are available at Sears and many other home improvement stores.