i have a 2007 macbook pro that started giving me problems for the last year on charging. id have to wiggle the cord at the connection and that would help most of the time so i bought a new charger and that fixed the problem for a while, also replaced the messed up cord on the original charger. for the last couple weeks it started not charging at all and the battery would go down really really quick, i mean in a few minutes. question is if my battery is completely dead would that prevent my macbook pro from starting even with the charger connected. shouldnt it run just off the charger by itself.