Here's how to install Avast Premium Security on Windows
A few easy steps is all it takes.
1. Click the button below to start downloading the installation file.
2. Once the download is finished, open the 
avast_premium_security_setup_online.exe file (by default, downloaded files are saved to your Downloads folder).
3. Click Install now and follow the on-screen instructions to complete the installation process.
4. Double-click the Avast Premium Security icon on your desktop to open the application, then go to ☰ Menu and select Enter activation code.
5. 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 installation instructions
That's it!
