RejZoR’s tool will clean more the the official avast tool https://skydrive.live.com/?cid=94a12102e5094675&id=94A12102E5094675!952&authkey=!AHu_KR3cJN1jHt4 once that has been completed you can run a search/find in the registry for Avast, if there’s anything left the search will find it.