car will not start on 2004 Dodge Stratus

while on lunch break my car died and will not start again. the starter works and turns the fly wheel but the crank shaft doesn't turn. And i can't turn the crank by putting a ratchet on it either. Does this mean the motor is locked up or is there a sensor that could be out? Any help or ideas would really be appeciated. David C.

Asked by for the 2004 Dodge Stratus
Check for oil in the engine, and coolant in the radiator but for the engine to have seized up you would have noticed a loss of power over heating and pining prior to the engine stalling.
Take out the spark plugs and see if you can still turn the engine over with the hand brake only on. It doesn't make sense that the starter turns the flywheel yet the crank pulley cannot be rotated unless something serious has happened to the nose of the crankshaft or the crankshaft pulley. The fan belt may have to be taken off for closer inspection of the pulley.
It does have oil in it and coolant in the radiator. There did seem to be a loss of power over the last few weeks before it died. But, I was just sitting in idle when it died. Do you know if there is a sensor that would lock the crank shaft if it went bad?