How do i replace a BMW 325i window switch?

The window switch can be pried out of the console, but do it carefully. But if the Windows are not working, there is a dashboard switch, on some models it is in a line of switches above the radio. That is the window lock-out switch so the children, if there are any, can not play with the Windows or adjust them inappropriately. Push that first to see if the lock-out switch is set in. Another thing to try before changing a switch is the fuse. There are on-line sources for the wiring diagram for your model.