ClamWin is a Free Antivirus program for Microsoft Windows 8/ 7 / Vista / XP / Me / 2000 / 98 and Windows Server 2012, 2008 and 2003.
ClamWin Free Antivirus is used by more than 600,000 users worldwide on a daily basis. It comes with an easy installer and open source code. 
You may download and use it absolutely free of charge. It features:

    High detection rates for viruses and spyware;
    Scanning Scheduler;
    Automatic downloads of regularly updated Virus Database.
    Standalone virus scanner and right-click menu integration to Microsoft Windows Explorer;
    Addin to Microsoft Outlook to remove virus-infected attachments automatically.

The latest version of Clamwin Free Antivirus is 0.98.7
Please note that ClamWin Free Antivirus does not include an on-access real-time scanner. You need to manually scan a file in order to detect a virus or spyware.
ClamWin Free Antivirus is based on ClamAV engine and uses GNU General Public License by the Free Software Foundation, and is free (as in freedom) software. To find out more about GNU GPL, please visit the following link: Philosophy of the GNU Project - Free Software Foundation.
ClamWin Free Antivirus uses ClamAV Scanning Engine