<human>: My car isn't starting. What are the possible causes and what can I do?
<bot>: Possible causes of your car not starting include a dead battery, an issue with the starter motor or alternator, a faulty ignition switch, or a problem with the electrical system. To determine which is the cause, you should check to see if the battery is working properly by testing it with a voltmeter; inspect the connections at the starter motor; test the wiring in the ignition switch for continuity; and check the power supply terminals on the alternator. If any of these components fail, they may need to be replaced before the car will start again.