Car won't start even with a jumpstart.
Do you know the condition of the battery? Sometimes a battery can be so bad that it will not allow the vehicle to jump start. If the battery is known to be good the next likely culprit for your concern would be the starter itself or the battery cables connecting the battery and starter. If the connections or cables are bad they will not allow electricity to flow to the starter properly and crank the engine. The last possible cause for your concern would be that the ignition switch is not sending the command to the starter to turn your engine over. I would enlist the help of a certified mechanic with the proper test equipment to pinpoint where the problem is and correct it.