I've had a Studio 1749 since 2010 and I still love it, but the original battery now no longer holds its charge. Dell don't seem to sell suitable batteries any more for this model, so I bought on on eBay, new and supposedly genuine. But before I insert it, how can I check? I've compared photos online and it looks ok, but would like to be more sure. I'm aware that the battery will have been produced years ago, as Dell probably stopped making them a while ago.