1. right click the avast ’ a ’ icon and select about avast, now look in the Registration key section (click the plus sign) and you will see the Updates expiration date.

  2. Three weeks before that date you will start to get Red pop-up alerts reminding you of the pending expiration. Then complete the avast! 4 Home Registration form and you will receive an email from register @ avast.com (without the spaces) with your registration key.

You enter your email address again with the re-registration.