I've just upgraded to Windows 10 from Windows 8.1, but after upgrading I can't connect to the Internet. I select my Wi-Fi network and click "Connect". Even though it says it's connected, I cannot open any page and the troubleshoot helper says that I'm not connected to any network.
After sleepless weekend got rid of this problem. It is Bitdefender TS in my case. Uninstalled it and Internet came back in a flash. Also updated all drivers for my Mobo Gigabyte D3H B85M from official site to Windows 10. Re-install latest version of Bitdefender TS. All fine now. Thank God.