my wife's car's electronics are not working (no central locking, no lights on the dash - nothing). I have tried charging the battery and jump starting the car but no luck. Could a bad fuse stop all of the electronics from working or is it something else ?
I am thinking an issue with the battery cables. Likely the ground cable. Follow it and see if it breaks anywhere.
Get a multimeter. Measure the voltage between the battery terminals, then between an unpainted part of the body or the engine and the positive terminal. If the voltage is about the same, your ground is good. If the voltage is 0, you have a bad ground. If your ground is good, you will need to follow the positive until you find a break.