OpenVPN Portable is openvpn and a modification of openvpn-gui, packaged with a PortableApps.com Launcher as a portable app, so you can take your vpn connection always with you. Unfortunately openvpn needs to install a network driver. This needs admin rights. OpenVPN Portable checks during the start process if the driver is installed. If not, the application asks for admin rights and installs it automatically.