If the engine won't turn over at all then it could be the starter motor, the ignition switch, or the immobiliser. Do you get a click when you turn the ignition to the 'start' position? any noises at all? Do the dashboard lights dim or go out?
Renaults are quite well known for remote locking and immobiliser faults. You probably need an auto electrician to go much further with it.
Chris
April 2007