Sentinel

Product: Sentinel 2.1
Company: RuntimeWare.com 
Website: www.runtimeware.com
Type: Free
Requirements: Windows 2000/XP

Sentinel works by analysing exploits in both your Registry and your system folders; integrating with ANY Anti-Virus program to quarantine these threats. Sentinel's Integrity Checker will notify your anti-virus/trojan application(s) if any file has been modified or added in any way whatsoever (using either a heavily optimized CRC32, SHA-1, MD5 or MD4 algorithm--for those of you who don't speak geek: Sentinel is fast, and very secure). Sentinel's RegWatch will watch over your startup registry entries, as well as other commonly exploited tactics viruses use to load--if any file seems suspicious, it is audited.