I dont recommend doing this unless you know how to carefully open/enter the insides of an electronic device.. you don't need any advanced knowledge, but you dont want to pointlessly destroy something.. Chances are if you dont know what to do, you know someone who knows enough to do it for you though.
Anyway.. Simply open up the nova, towards the top-middle seciton of circuits you will find a black circular disk shaped component.. Peel the sticker off it (if it hasn't fallen off on its own) to reveal a little hole in the top of the disk..
This disk is the chirper... Now Some people might be inclined to remove it, but I'm lazy and didn't want to destroy something beautiful..
All you need is a toothpick and some blu-tac. Start stuffing the blutac in.. I recommend not using the sharp end and not pushing too hard on the bottom, to avoid damaging the component (even though you dont need it to work).
stuff it in tight. Keep stuffing it in until the entire hollow section of the disk is filled with firmly packed in blu-tac..
Put the sticker back on if you like... Now you have a silenced Nova!
What you've effectively done is added a shock absorber to a moving part.. The electrics of the circuit are unaffected - the same amount of power is still put into moving the chirper to make the beep, but it just has to push up against all that rubbery blutac instead of air.
