I posted a response here, but it seems to have disappeared. Let's see if I remember what I said...
Did you look in Device Manager to see if the RealTek is still enabled?
Did you open the Network and Sharing page in Windows and configure your network, making sure it's set to use the RealTek and not one of the virtual adapters listed in Device Manager?
If you only ever got drivers from Dell's site, the "old" chipsets should work. If one of the current chipsets is newer than the one you're trying to install, you'll get a warning and you can just abort the installation.
If all else fails, you can try to Refresh the Win 10 installation. You shouldn't lose your files with a Refresh, but back them up first on external media. You will have to reinstall your apps.
You could also try booting from a USB with that MS Win 10 file and doing a Repair, not a clean installation...
Forum Member since 2004
I am not a Dell employee