Can't locate paid version of Avast, find only free version.

I have searched my computer trying to locate paid version of Avast but only find the free version. No wonder I keep getting ads to upgrade. I have the activation code but don’t know what to do with it. Should I remove free and download paid but then how do I get out of the payment loop.

Would have been helpful if you said what paid version it was:
http://files.avast.com/iavs9x/avast_pro_antivirus_setup.exe
http://files.avast.com/iavs9x/avast_internet_security_setup.exe
http://files.avast.com/iavs9x/avast_premier_antivirus_setup.exe

https://www.avast.com/faq.php?article=AVKB158