OpenVPN GUI installer fails to install the TAP32 adapter

Ever try to install the OpenVPN GUI from openvpn.se and have the tapinstall.exe fail?

Windows 2000/XP has a bug that it cannot properly detect new hardware by
*.inf files, if the RunOnce registry key is missing for the following
location:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion

This key is often used by installers to execute post-reboot programs, but
sometimes they accidentally delete this key.

IMPORTANT: This article contains information about modifying the registry.
Make sure that you understand how to backup and restore the registry, in
case a problem occurs. Please read the linked Microsoft Knowledge Base
article prior to editing the registry.

Go to Start Run and enter "regedit."

Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion

With CurrentVersion Highlighted, go to the Edit menu and select New Key

Name the key RunOnce, leaving everything else about the key alone.

The RunOnce key should now exist underneath the CurrentVersion key.
Once the key exists, Windows 2000/XP stops redetecting the Hardware

Now the TAP32 adapter will install.