Microsoft Windows operating systems feature Virtual Private Network (VPN) client and server software designed to establish a secure connection from a remote computer to a private network. Installing third-party VPN software or updates after configuring the VPN service on a Windows 7 or Windows Vista computer may delete WAN Miniports and prevent the computer from establishing VPN connections. Reinstall the WAN Miniport driver in order to resolve the issue.
Click the “Start” button, and then click the “Programs” icon, and then point to “Accessories.”
Right-click on the command-line icon in the menu that appears, and click “Run as Administrator.” The command-line icon will appear.
Type “devcon.exe install c:\windows\inf\netrasa.inf MS_PptpMiniport,” and press the “Enter” key. Reboot the computer, and the WAN Miniport driver should now be installed.