Security - first line of defense - OS patching

Microsoft products are target-rich environment for bot-creating drive-by dropper attacks, viruses and DoS ( Denial of Service ) attacks. One of the first line of defense against them is to make sure your OS has the latest patches.

There are 2 FREE applications that I found useful:

Microsoft Baseline Security Analyzer ( MBSA )
MBSA is a very simple and thorough way to make sure any MS-based computer is up to date and configured according to Microsoft best practices. My suggestion is to run MBSA after the second Tuesday of the month update from Microsoft or after any MS-mandated configuration change

Secunia Personal Security Inspector ( PSI ) Scanner
PSI scanner is the ideal compliment to MBSA because while MBSA deals almost exclusively with Windows Operating System, PSI inspects Microsoft applications as well as over 7,000 third party programs.

References
http://blogs.techrepublic.com.com/security/?p=478
http://secunia.com/vulnerability_scanning/personal/
http://technet.microsoft.com/en-us/security/cc184923.aspx