Click the “Start” button, click “All Programs”, then select “OpenVPN”, and click “Add a new TAP-Win32 virtual ethernet adapter”. This will create a new OpenVPN interface.
You may see a warning dialog box from Windows, continue the operation.
Next, Click “Network Connections” in the “Control Panel”. You should see a new TAP-Win32 interface. Rename that interface to something that you can more easily remember. I will use the name “tap-client1”.
You will need to disable Windows Firewall on this interface.