if you had the blue ball then you was/are using the old avast 4.x and support for this is about to end

you find the new one here…the free one

Avast! Free Antivirus 6.0.1000 http://filehippo.com/download_avast_antivirus/

On-line registration is very simple and it’s the preferred method for all users of avast Free Antivirus 5.x installed on a computer with standard Internet connectivity. To perform on-line registration follow these steps:
http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=459