1) Basics: Wifi switch, network cables
2) Repair Adapter
3) Reinstall Drivers
4) Boot in Safe Mode w/ Networking
5) Virus/Malware/Rootkit/Adware Scans
6) Ran Norton Removal Tool (even though I didn’t have Norton)
7) ipconfig /release /renew
8) Flush DNS
9) netsh winsock reset
10) No proxies set -> all default obtain automatically.
11) Uninstall all 3rd Party Firewalls/Antivirus, Turn Off Windows Firewall
12) Check hosts.ini has 127.0.0.1 localhost
Repair the Windows 8/7/Vista TCP/IP Stack
If you’ve tried everything you can think of to cure an Internet connection problem without success, it could well mean that Windows TCP/IP parameters have become corrupt. This often happens when a virus has been removed from your system but left behind some damage. It can also happen when you remove security software such as a firewall, which is deeply integrated with the Windows networking system.
To fix the problem you need to reset the Windows networking stack. Fortunately Windows 8/7/Vista comes with a built-in tool you can use to do this:
Click Start > All Programs > Accessories, right-click on Command Prompt and choose Run as administrator. Windows 8 users press [Windows Key] + [X] and select Command Prompt (Admin).
At the command prompt type: netsh winsock reset catalog and press [Enter].
Next type: netsh int ip reset reset.log and press [Enter].
Restart your PC for the changes to take effect.