A "Hidden Network" started showing up in list of networks.

When I refresh networks, I see all the networks I should (we have an extender, so there are two regions on our house) -- but I also see one called Hidden Network. How do I find out what that is? There are no nearby houses. This has to be emanating from my house.

It is most likely someone else that have their SSID hidden, which is actually false security. I would not worry about it. Due to it is not connected to your network in any way.

Usually you will find networks with no SSID, for the Utilities that use wifi radios for transmitting power, gas & water use. Also can be used to activate the Warning Sirens for EAS. I find them around our town on the 5ghz radio, Channel 11 all of the time.

Hello showmethefacts, and welcome to Eight Forums.

The listed Hidden network option is actually to select to connect to a hidden wireless network that is set to not broadcast it's SSID.

(option two)
http://www.eightforums.com/tutorials/37737-wireless-network-connect-disconnect-windows-8-a.html