No network connection after upgrading to Windows 10
I had the same problem, do you have VPN software installed? I had an old Cisco VPN installation and I couldn't remove it under windows 10. To fix I had to revert the upgrade and uninstall the VPN then upgrade again. My revert only took a couple minutes, it's usually very fast.
Open start menu and search for "windows 8" you will see a settings option to "Go back to Windows 8.1"
Uninstall VPN
Upgrade again