Norton is a bloatware-hog, Uses way too many resources and fcks your system config quite a lot...Personally I would dump it and find something worthy of being called AntiVirus or Firewall software.
Nothing easier, if you have a valid subscription to Norton 360, just go on Symantec's website, search for it.. install.. and it will transfer the remaining time of your subscription to Norton 360 v 2.0. I did it on my 3 PCs without a hitch.