Before you give Norton yet more money to cure a problem their AV should cure, read this:
http://www.pcmag.com/article2/0,1895,2342634,00.asp
They use the free version of Malwarebytes' Anti-Malware
http://www.malwarebytes.org
Get a friend to download it onto their desktop, save the set-up (.exe) file to CD or a flash drive, install on your pc. Run a full scan in Safe Mode http://www.computerhope.com/issues/chsafe.htm
If you can't do that, rather than pay Norton, get expert free advice from a specialist malware-removal forum, e.g.
http://www.malwareremoval.com
http://www.bleepingcomputer.com