Hi there,

Download the correct version and to get your paid license back just enter your email into the resend license link.

http://files.avast.com/iavs9x/avast_free_antivirus_setup.exe
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

http://www.avast.com/en-gb/resend-license-paid.php