My mother called the other day and told me about a problem she's been having with her 2002 Chevy Cavalier. About a month ago, the car would not start up and would only give a clicking noise. The car battery was replaced and that seemed to fix the problem. This past Monday the car did the exact same thing, no start with the same clicking. She had a neighbor charge the battery and that seemed to help for a day. This morning when she went to crank it up, the car started but was very weak and almost went dead. While driving she noticed the car had some difficulty accelerating and would only go about 45 - 50 MPH. I went with her to Auto Zone to have them check the battery and was told that the battery was good. The Auto Zone employee also performed a startup check on the alternator and was told that it passed as well. Any idea what could be going on?