i did use claimwin; its perfomance is average but few days laer i did notice that my HDD space got consumed without installing anything or download any file in my HDD and i was getting low disk space message then i did found claimwin reservs HDD space making lot of duplicate file and other temporary files in HDD; laer i did delete all those file and uninstal claimwin; now i am using Mcafee and i am happy now.

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.


The latest version of Clamwin Free Antivirus is 0.93


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.


Download: http://downloads.sourceforge.net/clamwin/clamwin-0.93-setup.exe