Installations and the keys

Hi

 

I have been running Norton Security for awhile.  When I pull up my account it shows no devices ? 

 

Yet under my account it shows my main computer in one seat and my laptop in another.  However I should have one seat free/empty and it doesn't show.  It shows an installation on the main computer twice.  Once in 2010 and once in 2014.  Not sure what I have done here.  I probably did install it twice on the same computer as I think I had that computer out of service for awhile and replaced with another.  Not sure if this means I can simply delete the first installation (2010). 

 

I ask all of this because I am wanting to use my 3rd key and install on my newest computer.  So I will have all 3 keys used up.  One on the laptop, one on the older main computer, and one on this newest computer (mentioned above).