Answer
This question was answered on November 25, 2005.
Much of the information contained herein may have changed since posting.
There are three systems that backup parts of the systems affecting the registry. The Emergency Repair Disk backs up the critical Boot Files. The Automated Systems Recovery lets you create a backup of your system for later use. The third and better one is the Backup Wizard which can be reached by going to the welcome screen and select the Backup Wizard and chose from the choices. The Backup Wizards third option can make an ERD file with Registry backup and Active Directory files. When you install Windows updates certain files may need to be backed up and if your Backup Wizard is kept updated you can go to the Backup Wizard to correct installation updates errors.