I had similar problems with mine - the passenger window stopped working, then a while later, the rear window would only go down and not back up.
I suspected that it was just gunk in the switches, and had been meaning to look at it for ages when I finally got round to it last weekend.
I took the switch pack out, sprayed it liberally with anti-static foam cleaner, agitated it a bit with a small paintbrush, sprayed some more foam cleaner on, toggled all the switches a few times, sprayed some more foam cleaner on, then left it to drip dry for about an hour. Repeated this 3 times, then left it overnight to dry properly.
Refitted the switch pack, and all my windows are working properly for the first time in months.
Note that you can buy switch cleaner, but I prefer to use the anti-static foam cleaner for a couple of reasons - depending on which solvent is in the switch cleaner it can react with the plastic, and also the foaming action of the foam cleaner gives it a chance to get in behind the switches and dissolve the gunk from the contacts better than a pure solvent cleaner.
I've recently switched to using Mykal De-solv-it as my anti-static foam cleaner of choice after using Electrolube for years. There are plenty of them to choose from, but I find Mykal has the edge in degreasing properties.