I think you will find this is the latest version of the removal tool click here
As a follow to removal of Norton,run ccleaner click here
Finally use Vista's search and type Norton and delete all it finds,same goes for typing Symantec and delete all it finds.
There is one other route and thats using the registry,this i would not advise unless you are confident with REGEDIT.
If you decide to search the registry,MAKE sure you backup the whole registry first !