this could be a multitude of things. First make sure the battery is charge with enough juice to actually crank the engine. Then verify that the crank shaft spins, perhaps it is stuck, pull a spark plug or both and insp for water and try to rotate dshaft by hand. Check the drive pump and make sure there is nothing jammed. chack your battery cables condition and if all is tight. also not neccesarily in order, but remove and check the starter itself- usually you have to start by asking yourself what and why this all happened since the last time you rode it. -good luck