See How do I back up, edit, and restore the registry in Windows 2000?
Microsoft Knowledge Base Article 322756 contains the following summary:
Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 Description of the Microsoft Windows Registry
NoteThe registry in 64-bit versions of Windows XP and Windows Server 2003 is divided into 32-bit and 64-bit subkeys. Many of the 32-bit subkeys have the same names as their 64-bit counterparts, and vice versa. The default 64-bit version of Registry Editor that is included with 64-bit versions of Windows XP and Windows Server 2003 displays the 32-bit subkeys in the following registry subkey, or "hive":
HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node
For additional information about how to view the registry on 64-bit versions of Windows, click the following article number to view the article in the Microsoft Knowledge Base:
305097 How to view the system registry by using 64-bit versions of Windows
