If it won't crank off the key and there's no spark either, it could be the start inhibit relay, big red one on the left row in the fusebox at the front if you are looking from the front of the car. I had this problem on mine about 3 months ago. The relay was fubar'd. Don't be fooled by the Haynes wiring diagrams, they say the relay is only fitted on auto cars but it's on all of them.