Is the engine turning over? Do you hear a clicking?
If the engine IS turning but not starting, since you got new battery it could be the starter, or the power wire running to the starter has to much resistance in it and its not getting full amps to turn engine.
If you just hear a clicking and the engine is NOT turning, it could be more in the control circuit of your starter and not just the power wire. Or it again could just be the starter.
Take it to a place that can do a "load test" on a batter and have them check your starter. If they dont know how to check the starter with it than smack them. All you do is hook up + and - clips to batter and hook them AMP meter to wire going to starter.
2000 GT - White - BAD @$$
-H&R SS Springs w/Koni Struts and Shocks, Flowmaster Mufflers, VT Stage 2 N/A cams & Performance 600 Lift Springs, SCT Hand held w/93 Performance Tune