Nothing is worse than heading out to your car, expecting a normal day, turn your car key … and nothing. What could it be? And how is this going to impact your day?
Finding the problem is simply trial and error. Start with the most obvious and keep looking until you find out the cause.
Dead Battery
The most common reason your car won’t start is due to a dead battery. How long since you’ve replaced it? Batteries won’t last forever, especially with severe cold and hot weather conditions. If you have a battery tester that can measure the cranking amps, test your battery and see if its weak. Or use jumper cables to jump-start your car. If it starts immediately, chances are it is a dead battery.
Battery Corrosion
Over time, your battery connections can become dirty. This corrosion builds up over time and actually breaks the connection your battery has with the rest of the car. A simple cleaning will remove dirt particles and return your car back to original condition.
Bad Ignition Switch
Battery issues are usually the most common reason your car won’t start. Yet if you’ve checked out the battery and it still won’t start, it may be faulty ignition switch. Turn your key to the on position – not all the way to start up the car. If the warning lights on your dash don’t light up, its probably the ignition switch. Another test would be to turn on your headlights and try to start the car. If they dim or turn off, your ignition switch is okay. If not, the switch needs replacing.
Bad Starter
Corrosion and buildup not only affects your battery, it an also affect connections within your 
electrical system.
Test the starter connection by having a helper hold a circuit tester lead on the wire that connects to the starter, which is the smaller of the two wires attached to the starter. Start up the car and check the current.
If power is running to the starter but it isn’t spinning, it needs replacing.
Still won’t start? The problem may be more complex: from electrical problems, to fuel pump issues, to a faulty computer system.
Trust your auto repair mechanic to check out your entire system, and get you back on the road.
Advise you also try to clean the battery connection, then try jumping it or recharging it, if it still doesn’t work then you need a battery. They cost around $ 100 for a good one. On average a car battery should last about 5 years but it depends .