Go to Control Panel > Add/Remove programs > avast! antivirus > Remove. Then choose Repair function in the popup window (Repair). You must be connected to the internet while repairing. If this does not help, can you uninstall / boot / install / boot again?
Strange fareed asked this same question on Sept 17 2006 and got the same answer banned license, but they didn’t protest they had a legitimate copy when kubecj gave that answer “Remove avast, install free home version and don’t use any of keygens again.” http://forum.avast.com/index.php?topic=23605.msg194678#msg194678
Yes, the first instinct is to help, rather than think the worst, no need to feel stupid for that. That someone with a pirated key has the affront to add insult to injury by asking for help in the official support site for the pirated software.
This we have to assume as ‘fareed’ didn’t respond to the original topic, which questioned the legitimacy of there copy and license, just wait a few of weeks and try again.