For whatever reason Microsoft has removed the ability to right-click wireless networks and forget them in Windows 8 and 8.1. Also, the wireless network manager has been removed since Windows 8 came out. In order to remove a wireless network from your list of networks that you automatically connect to:

1) Right click the Start Button and select Command Prompt
2) Type in: netsh wlan delete profile name=”ProfileName”
Where ProfileName is the name of the wireless network.
An example is netsh wlan delete profile name=”UWGB Wireless”
Press enter to run the command.

To view a list of remembered network connections, in command prompt, type in: netsh wlan show profiles

A full list of commands can be found here: http://windows.microsoft.com/en-us/windows-8/manage-wireless-network-profiles