Why won't it start?

Are you beyond 36,000 miles? Does the vehicle still have a factory warranty on it? If so, see your dealer and let them deal with it! If the vehicle has been salvaged or is over 36,000 miles, then it's going to need some good hands on troubleshooting. I have doubts about that battery; that's the most common cause of no starts. What mechanism are you using to "test" it?