its not the TDC sensor if it wont even turn over. I would be diagnosing it this way:
1. check voltage across battery, it should be around 11.5 volts
2. check voltage across the battery when trying to start the car, if it goes below 10vdc then the battery need replacing
3. if the above 2 are ok, then for voltage across the starter solinoid (this is the small wire not the big red one), if there is nothign being presented then its the ECU/immob
4. if there is good voltage across the starter solinoid, then check the voltage across the output of the solinoid and ground when attempting to start the car. if no voltage is present, then the solinoid is not firing
5. if voltage is present, then the motor has either had it or is stuck, rocking the car back and foward will release it if its stuck.
good luck.