If you're not using IPv6 (I assume you wouldn't be), you can uninstall it by executing the following command (I recommend doing such in a a Command Prompt):
ipv6 uninstall
If IPv6 was installed at the time of execution, you will see...
Uninstalling...
A reboot is required to complete this action.
Restart your PC to complete the process, as advised.
With IPv6 uninstalled, you _may_ be able to remove 'Microsoft Tun Miniport Adapter #2' from Device Manager.
If not, there's certain registry keys that can be deleted to prevent the service from starting up during Windows' boot.
ANYTHING PERFORMED BELOW IS DONE AT YOUR OWN RISK...
Perform a search for 'tun miniport' in Registry Editor (Start - Run - regedit) and delete the resulting keys. When doing a search on my PC, the following keys are returned:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\ Services\t unmp
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Servi ces\t unmp
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\S ervic es\tunmp