Did you register for the free license ??? and when the time is out you do it again

On-line registration is very simple and it’s the preferred method for all users of avast Free Antivirus 6.x installed on a computer with standard Internet connectivity. To perform on-line registration follow these steps:

How to
http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=612