Ethernet LAN Detection
"Make life easy for yourself and temporarily disable the wireless interface on the computah. Make sure that the ethernet interface is enabled. "
Just my two cents here - with what all it takes in Winblows to disable the wifi, it might be easier to just disable it temporarily at the router. If it is your router or is in your name you have the master password, so it is just a matter of typing an address in a browser and a few clicks later you have no wifi. It might pick up wifi from the neighbors but if you aren't or can't sign in, it should look for an internet connection and default to the ethernet.
That is unless they removed even more stuff from Windows, don't get me started on that, I still want 98SE back, it did more for me than anything since.. Now it seems everything I want automatic is manual and a big hassle, and everything I don't want automatic is and it screws it up half the time and takes more trouble to set it how I want it than it would to just do it in the first place.
Enough rant, I think my method will work and it might be easier. less typing at least.
Other than that I know nothing. (Sgt. Schultz voice)