Is it the card type key? These keys fail quite often, usually when dropped.
Do you have a spare key you can try?
There are a number of companies which can test and repair these keycards, if you can find one local to you they will usually test free of charge, just search for "renault key repair" and your nearest town/city.
This company seems to get good reviews-
www.keyrepair.co.uk
Reviews at-
http://www.reviewcentre.com/reviews200930.html
Renault dealer should be able to test them, but may well charge.
laguna
February 2011