hi all , it's been a while. I'm not a rich woman so I am hoping someone can point me in the right direction with my problem. My '85 mk used to start no worries , then it needed a little boost via jumper leads. Sometimes when i drive it and turn it off it won't start again without a jump. Do you think its the battery or alternator. I was going to test it with the volt meter but the battery in that is dead too . What are your thoughts before i spend money on a new batttery.