How TO Activate Avast With A Valid License File:
 

First Download a trial directly. Then Install it and during installation, use one of the license files, or install it as a trial, then follow these steps:
 
1. Right click "Avast Tray Icon" and and click "Open avast! user interface".
 
2. Click "MAINTENANCE" then "Subscription".
 
3. Now, if you have a license file With extension *.avastlic, then click "Insert license file" and navigate to where the file exists in your hard drive and open it, then click "Yes".
 
4. DONE!