Any administrator who has worked with computers running
Windows NT or any other Microsoft Windows systems should be familiar with the registry.
Microsoft defines the registry as “a unified database that stores
configuration data in a hierarchical form.”

In fact, the registry stores almost all system settings and
data. Control Panel and other utilities are actually nothing more than a
graphical front-end to the registry.

Of course, you can directly edit the settings in the registry
without using the Windows NT tools. However, as we’ve reminded you more than
once, this is potentially quite dangerous.

Unfortunately, there are times when you have no other options.
In these situations, make sure you have a verified backup of the registry
before you begin making any changes.

To back up the entire registry, you can use the Windows NT
Backup tool (Ntbackup.exe) and use the option to back up the registry. (You
must have a supported tape drive to use this option.) Or, you can also enter
the rdisk /s command at the command

Because the registry is a vital part of Windows NT, you
should perform regular backups—don’t just back it up when you’re editing it.
The best way to do this is to include the registry in your normal backup

Editing the registry is the process of physically modifying
the files stored on the hard drive that create this memory construct. The
registry includes five root files (or keys):

    This key contains information about file extensions.
    This key contains profile information about the currently logged-in user,
    including the user’s folders, screen colors, and Control Panel settings.
    This key contains information about all of the hardware and software
    installed on the system. It includes five subkeys: Hardware, Security
    Accounts Manager (SAM), Security, Software, and System.
    This key contains information about all of the system’s user accounts,
    including the default profile.
    This key contains copies of the information from all of the other root
    keys that pertain to the currently running session.