Have you ever been in this situation where you
First, let's explain the components involved in igniting the car and are responsible for starting the engine. The engine needs three things to start working: a starter motor, a battery, and a starter circuit. The battery needs to be charged above 12V and a fully charged battery will read 12.5V on a voltmeter. The starter motor creates sparks that ignite the fuel and air mixture when the car key is first turned. Besides that, the engine itself needs to be in a certain state when the car is started. It need for example a particular pressure level in its cylinders which is about 70 to 80 PSI. It also needs to open and close valves in the exact right moment. Many other things are required for the car to start properly. If your car fails when you start it, it means that one of the previously mentions requirements are not met because one of those components is faulty or malfunctioning.
Now to try to diagnose the problem, listen first for the starter crack. If you don't hear that cranking noise when you start the car, then it is probably because your starter motor is toast. If you have an automatic transmission car, make sure that the transmission is on 'neutral' because most cars install a safety switch that prevents the starter from cranking unless the transmission is in the proper state. Some manual cars have this switch in the clutch pedal which allows the starter to spin only if the pedal is fully pressed. If the cranking noise is fine, then look for the next problem, the battery. A battery charged to less than 11.8volts will be insufficient to start your engine. Get a voltmeter and attach it to the terminals of your battery and see the reading. If it is not above 12V, then you surely need to change your battery.
If you try all the above methods, and the car still doesn't work, then you need a professional's help. Go to http://www.lockbargains.com/locks_and_hardware/automotive/ignition-switch-locks.html for more help on ignition lock problems.