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If when you say that you have gotten the engine to start when you have jumped it then there have to be a low current problem some where. The first place I would inspect would be the battery post them self. Remove the battery cables and clean both the cable clamps and the battery posts. Replace them and see if that repairs the problem.
If that is good and the car start then the problem is solved should the car not start then inspect the earth cable from the battery to the body and from the body to the engine. Remove the terminals and clean the terminals and the spot where the cable bolt's onto the body.
This information should get you going as the fact that when you have jumped the car has proven that the starter and the ignition key system is in order. But please do not hesitate to ask if you need more assistance.