is there any kind of alarm installed on the car? some alarms have an ignition kill which will prevent the car from starting. also, try the main relay if you haven't yet. at this point, the problem has to be something so stupid that we've all overlooked it. are the plug wires on in the right order? you're sure everything is hooked up right and making good connection? there's not some stupid sensor somewhere that you left unplugged by accident?