My Toshiba C55-B5299 Laptop (Win 8.1) all of a sudden cannot see its built in Ethernet port. I use it because the Wi-Fi works, but can be flakey, and the Ethernet is more stable. I used to be able to see it in the device manager, but now the only way to see it is to use "show hidden devices" in the view menu. It shows a "Realtek PCIe FE Family Controller #2". When I click on it, it shows under the "general" tab the following:
Currently, this hardware device is not connected to the computer. (Code 45)
To fix this problem, reconnect this hardware device to the computer.