1996 GXE won't start

I was away this weekend and my brother borrowed my car and went up to PA. After driving and parking it up for about 2 days. Now it won't start after it was sitting outside for about 2 days. He got a ride back to NYC with some other relatives. I didn't get a chance to take a look at it myself. What could be wrong here? Dead starter? Frozen fuel lines? Fuel pump? I really think it might be the starter. How would I go about checking to see if my starter is dead? I used to hook a wire to positive of the battery and touched it to wire going into the starter when I had a 91 Toyota Camry, and the car would start. After the car started I would just remove the jumped connection between the starter and battery. Can I do the same to test my 1996 Sentra. Any other ideas on checking for any other problems would be appreciated


Thanks in Advance