Looked up MRT and most of what I found applies to the following program.
Not running Windows, but found this. Don't know if it applies to your situation or not.
Microsoft Windows Malicious Software Removal Tool
http://support.microsoft.com/kb/890830/
How to remove the Malicious Software Removal Tool
The Malicious Software Removal Tool does not use an installer. Typically, when you run the Malicious Software Removal Tool, it creates a randomly named temporary directory on the root drive of the computer. This directory contains several files, and it includes the Mrtstub.exe file. Most of the time, this folder is automatically deleted after the tool finishes running or after the next time that you start the computer. However, this folder may not always be automatically deleted. In these cases, you can manually delete this folder, and this has no adverse effect on the computer.
How to receive support
No-charge support is available for home users by calling 1-866-PCSAFETY in the United States and in Canada. For international users, contact your local Microsoft subsidiary. For more information about how to contact your local Microsoft subsidiary for security update support issues, visit the International Support Web site:
http://support.microsoft.com/common/international.aspx