Check that the wires are connected at the back of the starter. One big one that's hot all the time and one small one. With a test light, see if the small one's getting power when you turn the key to start. If not, check that the relay is working. You may be able to swap it with another relay in the fuse/relay box. Also, check all fuses. If swapping the relay doesn't help, we need to start checking the ignition switch. You could also have a faulty Neutral Safety switch. Turn the key to start and hold it there while you run the gear shift back and forth from drive to park. If it tries to start then, replace the safety switch on the transmission. Try that and get back with me. I like to know if I've been of any help.