My alternator went bad. so i bought a new battery to be able to drive the truck temporarily. i wasn't paying attention that the posts on the new battery were on opposite sides as the old one. when i hooked it up backwards, it fried my starter. i just replaced the starter and the alternator. my lights and everything like that works...but the truck still won't turn over. i checked the starter with a screwdriver. it's fine. what could be the problem?