Hello,
This is Mike from the Norton Authorized Support Team.
As the other person mentioned, fully removing AVG is the first step you need to take before installing Norton 360. Symantec has created a guide to installing Norton 360 which will hopefully resolve the issue you are having. Using Internet Explorer, please click on the link below and carefully follow the instructions for installing Norton 360.
www.symantec.com/norton/support/kb/web_view.jsp
If you still experience problems when trying to install Norton 360 after following the steps in the document above, please let me know so that I can assist you further.
Thank you,
Mike
Michael York
Norton Authorized Support Team
Symantec Corporation
http://service.symantec.com/priority