My 12" pb one day decided to act like the battery wasn't there anymore, I can't use it unless it is plugged to the wall, and when it is plugged in it shows an x where the battery indicater should be, so I called a couple friends with 12" pb's and tried their batteries and the same thing happened, so I called applecare and sent my pb to apple over the weekend and I get it back today with this response "Our analysis has determined that although your battery no longer has the capacity to function at a level necessary for the operation of your unit, it is not defective. I called them back to remind them that it is my pb and not my battery and was then instructed to purchase a new battery.