In Windows 7, type the following in the search box on the start menu:
view network connections
or you could type in the run dialog:
When this window opens your adapter will not be selected, so select it and go to the applications key for the shortcut option. To disconnect from the network hit enter on the shortcut, When this window opens tab to disable and spacebar it, and you are disconnected from your network. To re-connect, just hit enter on the shortcut again.
After disabling, you can go to the device manager and you will see that your adapter is disabled.