IMPORTANT: You will first need to enable OpenVPN password save feature in order to launch the OpenVPN connection at system startup. To do this please follow this FAQ.
Once you have this enabled, you can proceed with the second step which is to enable OpenVPN to run as a service.
By default OpenVPN service is set to 'off' in Windows services area .
To enable it, go to Control Panel / Administrative Tools / Services, select the OpenVPN service, right-click on properties, and set the Startup Type to Automatic. This will configure the service for automatic start on the next reboot.
With this in place, next time you boot your computer you will connect automatically to TUVPN network using OpenVPN !