XP Maximized: Microsoft Baseline Security Analyzer

Highly recommended.

The MBSA performs an audit of your computer's security, reporting the problems it finds and explaining how to fix them.

Download it at www.microsoft.com/technet/security/toois/mbsahome.mspx.

The theory behind the MBSA (Microsoft Baseline Security Analyzer) is that if software got us into a mess, it can maybe-just maybe-get us out of it.

http://www.xpmaximized.com