From mathcad 14 help, under "Exporting and Registering Components" in "The Developer's Reference"
---------------------------
To remove an MCM file from your system:
1.Open the Start menu in Windows, and click Run.
2.Click the Browse button. Navigate to your Mathcad program directory, and select the file mcmreg.exe. Click "OK."
3.In the Run dialog, add the following command-line arguments:
/u mcm\control.mcm
where control.mcm is the MCM file you want to delete; in this example, it is located in the mcm directory of your Mathcad installation. The "/u" removes information on the MCM file from the Windows Registry.
4.Once you have unregistered the component, it will no longer appear in the Component Wizard and you can delete the MCM file from your system.
---------------------------
Regards. Alvaro.