Be logged in, then click the deletion link. Be aware, this is a fast one. 🙂
URLS:
http://www.avast.com/
https://my.avast.com/profile#deleteAccount
Please note that AccountKiller.com is not associated with the business listed on this page. AccountKiller provides easy-to-understand instructions and guides on how to cancel charges and relationships from the list of businesses on our site, we have no affiliation with these businesses.