How do I get my Opel Monza running again?

Were baffled! Last year it conked out on me on the motorway after a car show. It started again eventually but ran very rough, and was pinking a lot under acceleration. Shortly after this, it started running ok again and then suddenly stopped starting completely. I changed the coil, the little black module attached to the coil, all the leads, the cap and rotor and eventually the distributor itself (for a second hand one I got hold of) Still nothing, it just turns over. I'm fairly sure there is fuel getting through but there is no spark at the plugs or at the dizzy. The ECU, spark advance module and the air flow meter are all ok because they work on my brothers Monza. The only other thing we can think of is that my touch key imobiliser has gone faulty and it wont "re-mobilise" the ignition. Any ideas? Ta!