Firstly, have you checked both fuse boxes. The main one is fitted under a facia cover on the drivers side (interior) and there is a fuse/relay box in the engine compartment next to the battery. I had this same problem on another car recently and it was the heater motor resistor which had blown. I do know that fiat punto's are fitted with resistors also and if they go then nothing on the ventilation will work.
Good luck
Craig
November 2006