Dee needs to uninstall Norton 360. Leo says that there are ways to do it and searching Norton forums will help. Norton also has stand alone uninstallers that will do it.
Once she has Norton off of her system, Leo just recommends recommends having automatic updates turned on in Windows 7. Then install Microsoft Security Essentials. It's a great, free, antivirus and running it will keep Dee's computer about as secure as she can. Ultimately though, her computer will only be as secure as her own behavior, which is the last line of defense. Be wary of getting links from friends or opening attachments.