Repair Network:

This will clear the stored DNS cache in Windows. When the DNS becomes corrupt you will not be able to get to some sites. Flushing and rebuilding the DNS will fix that problem.
Also resets Winsock entries & resets TCP/IP stack.

This repair will also restore the Winsock and Winsock2 registry keys.

These extra commands are run on Windows vista and newer.

netsh winsock reset all
netsh int 6to4 reset all
netsh int ipv4 reset all
netsh int ipv6 reset all
netsh int httpstunnel reset all
netsh int isatap reset all
netsh int portproxy reset all
netsh int tcp reset all
netsh int teredo reset all
