My car was acting fine and then one day i tried to start it and it wouldnt start. I tried jumping it and it started but right when i would turn it off i wouldnt be able to start it again. I put a brand new battery in my car and it still wouldnt start but all the lights on the dash came on so i know its not the battery. can only start it when it is jumped but once i turn it off again it wont start. have absolutely no idea whats wrong with it. please let me know what you think? could it be the alternator? my friend says that the new battery would work if it was the alternator.