How best to install a new copy of NIS 2012 over an existing but time limited installation?

Hi.

 

I had NortonInternet Security 2011 installed on my computer. I took advantage of the freee upgrade to NIS 2012. This runs out in a few days time.

 

I have a brand new retail copy (boxed) of NIS 2012.

 

What is the best way ti install the new license?

 

Should I un-install the current NIS 2012 then install the new copy?

 

I would prefer to keep my existing settings. So can I re-install the new copy over the existing version?

 

Or thirdly is there a way I can simply inpiut the new product key and keep the existing installatio with an extended time period?

 

Thanks for any help and advice.