Can you hear your starter click? Does your vehicle have factory anti-theft? If so is the security light on / flashing? I would start off by making sure you had power to the starter, you will have your positive cable of your battery going down to the starter, it should be hot at all times (use a test light), then you will have a smaller wire, (red w/ white in color). That should light your test light in the crank posistion. Other posibilities are your inhibit relay ( in the fuse box under the hood). A possibly seized motor, Ignition switch, or Park / neutral switch on the transaxle.