Hi there i would need to know more detail, if all windows then main relay faulty master switch faulty main window fuse blown, did they go separately or all at once
check fuses first Jock
If the master switch isn't working any of the windows and either are the other door switches the chances are it's a fuse or a main wire has a bad connections or has frayed or burnt etc.I'd go over all the fuse/relay charts closely and be sure that the their okay and there could be more then one fuse in that circuit too.
Hope that helps and best of luck.By the way if you want anymore help or advice feel free to ask.