If your computer crashes or is lost or stolen, you can still remove the license by going to MSP's License Login page. At the top, you will see links that say "license information | billing settings | manage installations | SMS account". Click on "manage installations" and you will see a list of all your licensed computers. Click the "Deactivate" button next to the computer you would like to remove.
Please note: If a computer is deactivated, in order to reinstall on that computer, you must reach out to firstname.lastname@example.org with a subject of "Reactivate disabled installation" and your activation code to reactivate it.