Microsoft has made available for download a network scanning tool for network administrators to be used in identifying host computers that do not have the Blaster worm security patch installed. The tool is available at http://support.microsoft.com/?kbid=826369.
A step-by-step guidance on how to install the patch for the Blaster worm can be found at http://www.microsoft.com/security or http://www.microsoft.com.au/downloads.