Lot of users (me also) switched from AVG to Avast Free antivirus as AVG 2011 disappointed most of users by eating system resources and slowing down system performance. Avast 6 released with Auto-Sandboxing technology, including for free version users, though Avast Free Antivirus is free to use, you still need to register it to get one year license key, otherwise your antivirus will expire after 30 days.
Registering Avast online is easy by entering your email address, but you need to do this every time when you install Avast.
Though requesting a registration key by filling a form is recommended for offline users, its always good to have an Avast license key available (even for online users) with you to enter and activate it for one year when a case of the reinstall is required.
Registering Avast to get One year free license key
1. Visit Avast Free Antivirus registration page, fill out the page by entering your email address and other mandatory details
2. After filling your details, click “Register for Free License Key”, you get a message that “registration was successful, license key will be send to your email address within 30 minutes after this registration”.
3. When you get the license key in your email address, copy it, open Avast User interface, Settings>Registration
4. Click on ‘offline registration’ (check the screenshot below), and click on ‘Insert the license key‘ and paste it into the field.