after i install Avast 5 free
i can’t update whether by manually or automatically, why?
avast version? os running? other sec-sw (maybe a firewall,…)?
[off topic: gets boring, asking over and over again…] 
What is your firewall ?
Does it allow avast.setup internet access ?
- If it does delete the entry for it and do a manual update, this should force the firewall to ask permission again.
Have (or did) you another Anti-Virus installed in this system, if so what was it and how did you get rid of it ?