Re-activating my account after Windows re-install

After a Windows re-install, I’m trying to get my paid-Avast protection back, but cannot find the way to do that, so I’m installing for now a free version. How do I do that?

I need to re install avast product paid for after pc crash

Go to this page http://www.avast.com/en-gb/resend-license-paid.php enter the e-mail address that you used to purchase the licence and it will then be sent to you