No starter operation?

I will preface this by saying I know just about nothing about cars. I have a 2006 Nissan Sentra that we've never had any problems with, but this evening it will not start. It will not turn over at all, and I hear no clicking or anything from the starter. All of the interior lights, headlights, radio, etc. Come on fine. The power windows and door locks also work fine. I can also hear the fuel pump when the car is turned to "on", so I don't think there is a problem there. We tried to boost the battery off of our other car (2008 Nissan Armada, although I doubt that matters) but that did not work. I am about to have the car towed to the dealership in the AM, but wanted to see if I am missing something. Is the starter our problem? I know this probably sounds lame, but I don't know how to check the battery connections to make sure they are okay. I guess that could be the problem too? Oh, and there is gas in the car. I don't want to waste a bunch of money having the vehicle towed if there is something obvious I am missing. Thanks for the advice.