First of all click "start" then "control Panel". Find the tab "Network connections" and run it. If you have enabled the display mode category, then the tag will be in the section Network and connection to the Internet". Find it in the list of connections that you want to delete.
Deleting network connections there are some limitations. If unnecessary network connection is part of a network bridge, before deleting itself delete the network bridge (which can then re-create if you need). It is not necessary to remove independently of the virtual connection created by network programs (for example, adapters of the virtual private network created OpenVPN or Hamachi )- they are removed from those programs. Does not make sense to remove the network cards and adapters IEEE-1394 (Fire-Wire) - they will still be created by the operating system anew on the next reboot. Part of the described connections just can't be removed - the menu item "delete" is not available for them.
Then simply click the connection right click and select "delete"