Norton Removal Tool.
If still a problem after running that tool and rebooting ...
(From a JohnWill post)
TCP/IP stack repair options for use with Vista.
Start, Programs\Accessories and right click on Command Prompt, select "Run as Administrator" to open a command prompt.
Reset WINSOCK entries to installation defaults:
netsh winsock reset catalog
Reset IPv4 TCP/IP stack to installation defaults.
netsh int ipv4 reset reset.log
Reset IPv6 TCP/IP stack to installation defaults.
netsh int ipv6 reset reset.log
Reboot the machine.