Run Windows NT's built in tape backup program and select the Backup Local Registry check box in the Backup Information dialog. NTBackup can not back up or restore the registry of a remote computer - only the local system.
Rdisk copies critical portions of these files for recovery purposes to %systemroot%\repair. Rdisk must be run with the /s parameter to include security and sam data. On the Repair Disk Utility screen be sure to click on the Update Repair InfoCreate Repair Disk or again you will have a repair disk without current security and sam data.
The NT Resource Kit utilites, regback and regrest, can be used to backup and restore the hive files for hkey_local_machine or hkey_current_user.