check your battery cables and you ground. You may want to check your alternator, if the car only starts when jumped started. IMprovement to answer: If the new battery doesn't start the car, obviously it's not the alternator causing the car not to start... Check the starter relay under the hood if it is equipped and if that works then check the starter solenoid located beside the starter motor. If that's working then you can be pretty sure it's the starter motor causing your problem - maybe worn brushes or excess resistance in the circuit.
try checking your fuses and fuse-able links
Yes, the battery starts the engine, and as long as the battery is fully charged the engine will start. The battery will loose it's charge if the alternator is defective and not replenishing the charge of the battery but the alternator has nothing to do with starting the engine.
This could be the voltage regulator. Both the positive from the battery and the starter would be connected to it.
start by having the battery checked. If the battery is good, then check the starter relay. If this is bad, repalce the starter. Also check battery connections. Sometimes they can seem tight but just aren't. Take them off the battery terminals and clean them. This will also stop your batter from charging.
Check the battery, it might be low. A low battery can be caused by either an old, worn out battery or by a faulty alternator. If the alternator isn't putting electrical energy into the battery, the battery won't get charged. After all, a battery is only an electrical STORAGE device. If your battery is fine, you might have a weak starter. You should also check your ignition switch. Try disconnecting it, and then touching the female end to the battery. This grounds out the circuit, should start your car for you, and tells you your battery and starter are perfectly fine.
try checking your fuses and fuse-able links
battery
In most cases a new battery will be charged enough to start the vehicle
the only way to start a car when the remote key is dead is to start it by putting the key into the ignition.
absolutely nothing
Could be your park/neutral switch try putting the car into neutral and and then starting it.
Engine ground can find many paths to the battery, but if NOTHING is connected to the negative post... no, it won't start.
first find out if the engine is getting spark or fuel. if the engine is not turning over or absolutely nothing is happening, find out if the starter is receiving current.
what kind of "not start" ? Won't turn over? Nothing? What are the symptoms?
I would start by checking the battery and fuses.
Dead battery? Loose or corroded battery cable? Blown fusable link?
Yes, the battery starts the engine, and as long as the battery is fully charged the engine will start. The battery will loose it's charge if the alternator is defective and not replenishing the charge of the battery but the alternator has nothing to do with starting the engine.