None of the window switches work and the fuse is fine, where do I start to look for the cause???

I would check the power window relay in the relay/fuse block in the engine compartment behind the battery. Once you find the relay, swap it with another of the same size and color. Just make sure that it's a relay for a system that isn't important like the windshield wipers. The relay/fuse block cover will have labels for all the fuses and relays printed either on the top of the cover or on the inside. This test will rule out the relay and is the most likely cause since none of the windows work. If this doesn't work, then check for power at each window with a non-powered test light. If you have power at each switch and motor when the switches are depressed in either direction and still nothing works, you will need to check for high resistance in the ground circuits and motors themselves with a Digital Volt/Ohm meter. I hope this info helps!