How to Properly Upgrade to Norton AV 2011?

I have Norton AV 2010 and it is due to expire in less than 30 days.

 

My question is: Do I need to uninstall it before installing Norton AV 2011? Or will the Norton 2011 software install itself over the top of 2010?

 

I have had horrible issues in the past when trying to upgrade AV software, so need to make sure I do it correctly this time.

 

Thank you.

 

P.S.

I will be inserting a CD of Norton 2011 for installation, if that is helpful to know.