Disconnect from the Internet
If you have a dial-up connection to the Internet, you have to disconnect each time when you're finished using the Internet. If you have a broadband connection, you're always connected to the Internet, whether you're using the web or not. So when you close your web browser, your computer is still connected to the Internet.
To disconnect from a dial-up connection
Click the Connection
in the notification area, click the connection name, and then click Disconnect
To disable a broadband connection
Although broadband connections are always on, you might need to disable the connection for troubleshooting purposes.
Open Network Connections by clicking the Start button , and then clicking Control Panel. In the search box, type adapter, and then, under Network and Sharing Center, click View network connections.
Right-click the broadband connection, and then click Disable.
If you're prompted for an administrator password or confirmation, type the password or provide confirmation.