Download free Avast PC antivirus with web shield and real time protection
Avast! Home Edition is one of the best free anti-virus applications. This edition is free for non-commercial & home use only.
Anti-spyware built-in, Web Shield, Anti-rootkit built-in, Automatic updates, Strong self-protection, Virus Chest, Antivirus kernel, System integration, Simple User Interface; Integrated Virus Cleaner, Resident protection, Support for 64-bit Windows, P2P and IM Shields, Internationalization, Network Shield.
Note that Avast can become annoying with promotions of its commercial version and with false alerts. You may also like to check this post on how to reactivate Windows Defender after uninstalling Avast.