When deciding what tool you are going to get to backup your XP, 2000, or 2003 Registry be sure that is backs up the entire Registry. On these operating systems, not all Keys can be read by software. The Kernel32.dll protects certain Keys from being read, and other Keys from anyone being able to change them. Since the Kernel32 is protecting them, they cannot be backed up, not even exported by RegEdit. There are also many Keys that can be read but not changed and these Keys can be backed up but not restored. Since you cannot change them, you cannot write to them. Therefore you cannot copy the Registry files in Windows.
Every Registry Backup utility that I have tried, with the exception of WinSafe XP cannot backup and restore the entire Registry. The process that these other programs use is a function of Advapi32.dll; the call is"RegSaveKey" for each Key in a Registry Hive. You can verify this but trying a Registry backup tool other than WinSafe XP and compare the size of each Registry file to the backup file it makes. You will see that their backup files are much smaller than the actual Registry files themselves.
Since most Registry backup tools use the "RestoreRegKey" call, they are relying on the Kernel32 to backup and restore the information. However the Kernel32 will not, backup a Key that is protected. If a secure Key becomes corrupted this method will not restore that secure Key.
The only sure way to backup and restore a Registry is to copy the Registry files in there entirety. This is something you cannot do from inside Windows, the Kernel32 is protecting the files and will not allow you or any program to copy them.
WinSafe XP works differently then other Registry backup tools. It makes a copy of the Registry files stored in System Restore. These file are only protected against Users seeing them. System Volume Information is where System Restore stores its' backup information. Winsafe makes its' backup of the Registry files by copying System Restore information.
So WinSafe XP has a complete set of Registry files, including the complete Security and SAM files. When you need to restore the Registry, Winsafe will replace the entire set of Registry files. Not just with the Keys that can be read, but all the Keys, even the Secret Keys and protected Key.
WinSafe's restoration is done outside of Windows, in the Recovery Console where the Kernel32 is not protecting the Registry. WinSafe XP will replace the entire Registry, not just some Keys.