As per: http://lindsaar.net/2009/1/5/windows-ipconfig-does-not-show-anything
You can do the following at a CMD prompt to reset the network configurations:
C:\> netsh winsock reset catalog
C:\> netsh int ip reset reset.log
The first line resets all the WINSOCK entries to their defaults, the second line resets all the TCP/IP entries to their defaults.
The first one will ask you to reboot, don’t. Do both commands and then reboot your system.
