Microsoft Malicious Software Removal 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. This tool will help to remove specific, prevalent malicious software from infected systems. Because computers can appear to function normally when infected, Microsoft advises you to run this tool even if your computer seems to be fine. In addition to using this tool, you should use an up-to-date antivirus product to help protect your computer from other malicious software.