Force Windows to update registry backup

How to back up, edit, and restore the registry in Windows 2000
http://support.microsoft.com/kb/322755
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Note that if you use the option to back up the registry when you create an ERD, Backup also creates updated copies of the registry files in the %SystemRoot%\Repair\Regback folder. If you cannot start Windows 2000 after you edit the registry, you can manually replace the registry files in the %SystemRoot%\System32\Config folder with the copies in the %SystemRoot%\Repair\Regback folder by using Recovery Console.


How to Update the Repair Folder in Windows XP Using NTBackup
www.winhelponline.com/blog/update-repair-folder-xp-using-ntbackup/
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7. When the Backup Status changes to Backing up files from your computer…, click the Cancel button to stop the System State Backup operation. By that time, the Repair folder would have been updated.