I troubleshooted a peculiar problem today and to implement a workaround for that issue, I have to disconnect wireless at the time of logoff. I did some search in google and the below command helped me.
netsh wlan disconnect
Btw, this command is Vista/Windows 7 compatible. I am not sure about other operating systems. I did some more research and came across bunch of commands using which we can manage wireless on windows 7 computers very easily.
Refer to this Microsoft Document to know the commands.
Happy learning and happy Diwali.