Once the download is finished, open the avast_premium_security_setup_online.exe file (by default, downloaded files are saved to your Downloads folder).
Double-click the Avast Premium Security icon on your desktop to open the application, then go to ☰Menu and select Enter activation code.
Click the text box below to copy your activation code, paste it directly into the application by pressing the Ctrl and V keys simultaneously, then click Enter.
See detailed activation instructions
Type the activation code you received with the product into the text box, and click Enter(if asked, enter your name, email, and postal code).
See detailed activation instructions
To open the application, double-click the Avast Premium Security icon on your desktop.