Microsoft Security Essentials
From hacktolive.org
Microsoft Security Essentials is a free anti-malware (anti-virus, anti-spyware, anti-trojan, anti-rootkit) software from Microsoft.
Homepage: http://www.microsoft.com/security_essentials/
Definitions for offline installation/updating: http://www.microsoft.com/security/portal/Definitions/ADL.aspx
See also: Microsoft Standalone System Sweeper