Per Adapter:
- Click the Start button.
- Click on Control Panel.
- Click on View Network Status and Tasks
- Click on Change adapter settings
- Right-click the shared connection and choose Properties
- Click the Sharing tab
- Clear the Allow other network users to connect through this computer's Internet connection checkbox
- Click OK
System Wide:
- Click the Start button
- Type: services.msc and press ENTER
- Double-Click on Internet Connection Sharing (ICS)
- Change Startup Type to Disabled (or in some cases you only need to press the "Stop" button).
- Reboot the computer
- You can now try reinstalling the AnyConnect VPN client again.