My Scenic Renault won't start - alarm related?

Hi,

my scenic renault won't.
I put the card into the reader and press down on clutch and then the start button but nothing happens. The dashboard shows a red flashing light which indicates the alarm is still on and therefore car will not start. Could someone please advise - how do I reset the alarm as this may well fix the problem.
Thank you.

Fred
April 2013