1. Right-click the Start button and select Device Manager.
2. Expand Network adapters and find the Ethernet card (usually listed as "RealTek USB GbE Family Controller").
3. Right-click it and select Properties. The Device status should say the device is working properly.
4. If the Ethernet controller shows a question mark or exclamation point, reinstall the driver using the file below.

Download the Windows 10 RealTek drivers (ZIP)