has you have not stated what year the clio is , if its a clio 2 1998 onwards ,what you need to do is put the key in the ignition ,and switch the ignition on , keep your eye on the red led on the instrument panel if the light comes on and after afew seconds it goes out then this is ok , if the light is flashing then there is a problem with either the key ,or reciever ring round the ignition barrel ,or even the uch it has to diagnosed, as it could be the wiring also from the uch to the injection computer ,or something as simple as a relay in the engine compartment,Is there another light on the dash or do they all go out when the you try to start the engine and do they stay out due to the fact that clio 2 suffer from water ingress in the fuse /relay box in the engine bay also suffer from corroding wires and relay terminals corroding ,you need to check, and also i have come across afew now where the earth wire coming from the injection computer to relay the wire has broken there for the engine will not start hope this helps .
mark
May 2008