I have a 3 1/2 year old Macbook, my Applecare has ran out. About six months ago my computer began shutting off immediately when unplugged. (Was letting my roomates use the computer, came home one day and it started doing this.) I believe that my battery is OK, it performs between 97% and 99% consistently. When I do the battery test, all of the lights light up. I've read through the forums and it seems a lot of people are having this problem, but their batteries are bad. What are some options/solutions to this problem? I am willing to invest money wisely into the computer to keep it running smoothly for a while. Thanks!