Check the main fuse in the fuse box front left inside the bonnet    should say (main fuse)   its a 60 amp . and check if the negative between the body, battery,and engine (connect to gearbox ) if they clean and connected.
Hope it help.
Reason about fuse was mine had a similair problem   currently it runs with a thick wire link in the fuse's place bit dodgey but it works .
                
 battlecat
                
 January 2007