Yesterday it was 10 degrees Farenheit and my usually trusty subaru would not start (turned over but didn't start). This car has its original battery. I had AAA come out and jump it, then drove it to Napa auto parts. The guy there tested the battery and said it was fine (holding a charge etc) and I did not need a new battery. I asked if the car should start now and he said it should. He did suggest that I clean the terminals with baking soda- as apparently there was some corrosion that he claimed might cause problems with cold weather starting. Drove my car around for about 20 minutes or so running errands (kept engine running) and brought it home. About four hours later, same problem, turns over will not start. So any ideas? My temptation is to try to clean the terminals and if that doesn't help, jump it and drive it over to the dealer so they can have a look. If it isn't the battery then what is it? If I do need a new battery what model is recommended? Cold weather is anticipated for the next few days. I appreciate any advice that might be offered.