If the switch (on/off) on the lower part of the master switch fell off all you need to do is stuff some tin foil in it and it will complete the circuit and all the windows will work again. Sounds crazy but it is true!
Here is mine...
That is stuffed with tin foil inside with the switch removed and covered with a piece or cardboard with black tape on it for a nicer look!
Here is how you do it...
(1) Remove the on/off switch unless it already fell off like mine.
(2) Stuff tin foil in tightly where the below graphic shows.
(3) Dress up as appropriate, the foil needs to be tight in there and could come loose occasionaly so don't over do it too much.
I used a metal bracket to pressure the foil in and it hasn't come undone in about 8 months.
-Ben