Why does my camera on auto mode not work at all sometimes?

On auto mode and sometimes other modes, the camera will not work at all. Sometimes the zoom will go out at my command and then just come back to the beginning point. It will not even take a picture when it's doing that. At other times, it will work for a while. If I take the battery in and out, it may restart it and work OK for a while. Then, it won't work again later.