Hi
If you can try a CLI, DOS box then perhaps some light may be shed....
C:\>getmac
Physical Address Transport Name
=================== ==========================================================
44-44-DA-DE-66-27 \Device\Tcpip_{}
44-44-DA-DE-66-28 Media disconnected
C:\>getmac
Physical Address Transport Name
=================== ==========================================================
44-44-DA-DE-66-27 \Device\Tcpip_{}
44-44-DA-DE-66-28 \Device\Tcpip_{}
Using getmac command I can show an ethernet and WiFi adapter, and when I plug in a cable both are working.
So can you please give much fuller details on the PC etc.
Make Model etc, and what software you have and also any recent changes.