ClamWin is a Free Antivirus program for Microsoft Windows 98/Me/2000/XP/2003 and Vista. ClamWin Free Antivirus 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.
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.