Hi,
Please follow these instructions for a clean uninstallation of your Norton AntiVirus and to cleanly install Norton Internet Security. Please ensure beforehand that the latest version of Norton Internet Security 2011 (NIS 2011) meets your system requirements (go to "System Requirements" at this link):
http://us.norton.com/internet-security/
As the others have said, you need the Norton Removal Tool to cleanly remove Norton AntiVirus.
Note: the removal tool will wipe out your settings and any other Norton products installed on your computer.
-download NIS 2011 from here and save it to your desktop:
www.norton.com/nis11
-download the Norton Removal Tool from here and save it to your desktop:
http://www.symantec.com/norton/support/kb/web_view.jsp?wv_type=public_web&docurl=20080710133834EN
-make sure you have got your NIS 2011 product key handy.
-deactivate any other security software you may have, such as Windows Defender. However, please leave Norton running. As a side note: running two real-time security programs on one machine is not recommended.
-create a system restore point
-disconnect physically from the internet (remove the internet cable) as a precaution.
-if you are in Vista or Windows 7: right-click on the removal tool icon, run as administrator; run the removal tool 2 times to remove Norton AntiVirus, rebooting each time after every run. Rebooting should happen automatically.
-after running the removal tool: if in Vista or Windows 7: right-click the NIS 2011 icon, run as administrator, let it install itself. When it wants to connect with the web, connect again to the internet. In order to activate NIS 2011, type in your product key. Run LiveUpdate afer installation and reboot your computer.
Instructions taken from my posts in the Norton Community.