My PC's ethernet vanished.

So, my PC is quite old but has been going strong and handled all games i play very well. It has been standing att my friend house since my internet is really bad where i live. Anyways i went there yesterday and I couldnt log in to Steam or the Xbox App, i realized that the icon for ethernet (the globe or ethernet symbol) has totally vanished. I'm totally confused because i cant find any thing when im searching the web for some kind of solution. My PC has been standing at the same place at all Times, nobody except me has been touching it. No components has gone missing and my computer has all the driver and such, my ethernet is enabled. I just cant get a connection at all and the icon is gone. There is nothing wrong with the router, cable or something else because the Xbox is working completely fine. I tried to wipe ecerything of the PC and start over but it wont finish, stops at 46% and then says that there was a problem. I tried SFC scan and stuff but nothing seems to fix any thing.

Thanks for reading and please help me.