MS Malicious Software Removal Tool

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The Microsoft Windows Malicious Software Removal Tool checks computers running Windows Vista, Windows XP, Windows 2000, and Windows Server 2003 for infections by specific, prevalent malicious software—including Blaster, Sasser, and Mydoom—and helps remove any infection found. When the detection and removal process is complete, the tool displays a report describing the outcome, including which, if any, malicious software was detected and removed.
Microsoft releases an updated version of this tool on the second Tuesday of each month, and as needed to respond to security incidents. The tool is available from Microsoft Update, Windows Update and the Microsoft Download Center.
Note  The version of the tool delivered by Microsoft Update and Windows Update runs in the background and then reports if an infection is found. If you would like to run this tool more than once a month, use the version on this Web page or install the version that is available in the Download Center.

Because computers can appear to function normally when infected, Microsoft advises you to run this tool even if your computer seems to be fine. You should also use up-to-date antivirus software to help protect your computer from other malicious software.
To download the latest version of this tool, please visit the Microsoft Download Center
To download the x64 version of Malicious Software Removal Tool, click here.