Last night I received a brand new battery in my computer, because it the computer would not charge with multiple chargers. After it was replaced it was working for over 12 hours; however, it stopped working this morning. I called Apple and they told me to take out the battery. It was then again charging for several hours. When I plugged in about an hour ago, it was again not working. I took out the battery and put it back in and it is again working. What could be the root cause of this? Is there something in the structure of the computer which is affecting the performance of both my old and new batteries. The mother board and hard drive was recently replaced along with the keyboard and side panel, if that helps in your assessment.