Welcome to Windows 7 Support forums,
We have little information to make intelligent diagnostic.
Deducing from your initial post are we to gather that you are using a router connection? If so what type and manufacture?
If you are attempting to disconnect your ip address whats confusing me is are you doing it thru OS 7 command line or through your router?
If you are using your router access it via your web browser or through windows 7 using the lower right side tool bar by opening netwrk sharing and follow the trouble shooting guide. (See Attached Image). Or by using your browser type the following command in the upper left of the address bar: http://192.168.1.1
The browser will connect into your router provided you are connecting that way and then enter your user name and password, if you have not set it up the default is usually admin, admin