Hi, welcome to the forums, the failure of Norton might have been a symptom of some other problem on your computer. Now have you properly uninstalled it? You need to run the Norton uninstaller:-
http://service1.symantec.com/Support...05033108162039
Now McAfee is not any better you need to be rid of it as well. Use AVG free or Nod32 and enable the windows firewall.
Vista does not play well with the "security suite" offered by these companies they are simply not suitable for home users.