installed msd box now car wont start

if you are positive its wired up correct then test the box, pull your coil wire out of the distributor, lay it near an intake bolt, unplug the magnetic pickup wire, strip both ends of two pieces of wire, stick one wire in each side of the magnetic pickup wire, now turn the key to the run position, touch the ends of the two wires together that you just stuck in the magnetic pick up wire, then take them apart, each time you touch them and break the connection it should throw a spark from your coil wire