One possible solution for "No Cast devices found."
This weekend, while trying to cast a tab in Chrome, ran into the "No Cast devices found." issue that a number of people have complained about. Thankfully, I found a solution quickly and without much frustration.
In my case, I had been running a VPN connection using OpenVPN on a windows TAP adapter. Apparently, when the connection is active, and therefore the virtual adapter, the Chrome plugin gets confused and starts attempting to discover your Chromecast on the VPN adapter. Once I shut down the VPN tunnel, the Chromecast was successfully discovered.
So, in summary, if you run into this issue, and are running VPN tunnel(s) and/or virtual adapters in windows, try disconnecting or even disabling those virtual network adapters.
Hope this helps someone else out there!