Hi Christine,
Exactly the same has happened to my 53 plate scenic.  One minute working fine and not the next, no air flowing at all.  Take the car to a halfords to see if a fuse has blown.  Your fuse box is situated in the glove compartment in front of the passenger seat.  I wasn't as lucky, they said all my fuses are ok.  So car is going into garage tomorrow, just hope its not gonna cost me an arm and a leg this side of christmas.  Will let you know what they say and how much they charged me.
HTH X
                
 vicki
                
 November 2010