This tool checks your computer for infection by specific, prevalent malicious software (including Blaster, Sasser, and Mydoom) and helps to remove the infection if it is found. Microsoft will release an updated version of this tool on the second Tuesday of each month so users with Automatic Updates feature set to auto should get an updated version automatically.
Download the tool from here – http://www.microsoft.com/en-us/download/details.aspx?id=16
