Before you begin installing Avast Free Antivirus, ensure you are logged into Windows with administrator permissions, no other programs are running in Windows, and any other antivirus software is fully uninstalled.
- Windows 10 except Mobile and IoT Core Edition (32 or 64-bit); Windows 8/8.1 except RT and Starter Edition (32 or 64-bit); Windows 7 SP1 or higher, any Edition (32 or 64-bit); Windows Vista SP2 or higher, except Starter Edition (32 or 64-bit); Windows XP SP3, any Edition (32-bit)
- Windows fully compatible PC with Intel Pentium 4 / AMD Athlon 64 processor or above (must support SSE2 instructions)
- 256 MB RAM or above
- 2 GB free space on the hard disk
- Internet connection is needed to download, activate, and maintain updates of the program and antivirus database.
- Optimally standard screen resolution not less than 800 x 600 pixels is recommended.
- Avast Free Antivirus is not supported on Microsoft Windows Server operating systems, or any operating systems which are not specified.
Install Avast Free Antivirus
To install Avast Free Antivirus on your PC, follow these steps:
- Download the offline installer for Avast Free Antivirus by clicking the button below: Download Avast Free Antivirus ...and save it in a familiar location on your PC (such as your Windows desktop).
- Right-click the downloaded setup file
avast_free_antivirus_setup_offline.exeand select Run as administrator from the context menu.
- When prompted by the User Account Control dialog for permissions, click Yes (or Continue).
- Click Install to proceed with default installation.
- Select Customize to proceed with custom installation.
- Click Change to manually select the location to save Avast Free Antivirus program files, then select or deselect program components to install, and click Install.
- Click Continue.
- Review the Avast Privacy Policy and click Continue.
- If prompted to install Avast Free Mobile Security, click the relevant option according to your preference.
Avast Free Antivirus is now installed on your PC and ready to use. The Avast user interface is accessible via the 
Avast system tray icon on your Windows taskbar or the Avast icon on your Windows desktop.
To register your Avast Free Antivirus, go to Settings ▸ Subscription and click Register now. Registration in the latest version of Avast does not require you to enter your contact information. For more information, read the following article:
- Avast Free Antivirus 17.x
- Microsoft Windows 10 Home / Pro / Enterprise / Education - 32 / 64-bit
- Microsoft Windows 8.1 / Pro / Enterprise - 32 / 64-bit
- Microsoft Windows 8 / Pro / Enterprise - 32 / 64-bit
- Microsoft Windows 7 Home Basic / Home Premium / Professional / Enterprise / Ultimate - Service Pack 1, 32 / 64-bit
- Microsoft Windows Vista Home Basic / Home Premium / Business / Enterprise / Ultimate - Service Pack 2, 32 / 64-bit
- Microsoft Windows XP Home / Professional / Media Center Edition - Service Pack 3, 32-bit