Introduction
The Windows registry is the database used by Windows 95, 98, Me, NT, 2000, XP, and 2003 to keep track of the settings for the operating system and all installed programs.

Registry files
While Windows 95, 98, and Me store the registry in two files (system.dat and user.dat), Windows NT, 2000, XP, and 2003 store most registry information in files called "hives". Hives are stored permanently on the hard drive and are not necessarily the same from one computer to another. Only administrators can access hives or delegate the rights to access them. Hives for the "Machine" keys are found in the system32 directory, within the Windows directory, which is on the drive where Windows is installed. For example, if your computer has Windows NT or 2000 installed on drive C:, then you'll find hives in these directories

Editing the registry
You can edit the registry from a command prompt by entering regedit (in all Windows versions) or regedt32 (Windows NT and 2000 only). The regedt32 program is the more powerful (in Windows XP and later, regedit is equivalent to regedt32), as it can also search the registry on other computers on the network.
Warning: Edit the registry at your own risk. If you make an error while editing the registry, you can potentially cause Windows to fail or be unable to boot, requiring you to reinstall Windows. Always back up the registry before making any changes. For information on how to back up your registry, see the Knowledge Base document In Windows NT, 2000, and XP, how do I back up the registry? or In Windows 95, 98, 98SE, and Me, how do I make a backup of the registry? If you feel uncomfortable editing the registry, seek the help of a computing support provider.

The registry in older versions of Windows
In Windows 95 and 98, you can also use the System Policy Editor (Poledit.exe) to edit the registry. The System Policy Editor allows you either to create system policies or to edit the registry, depending on whether you are in Policy File mode or Registry mode. The System Policy Editor is easier to use than the Registry Editor because it requires less knowledge of the registry structure or syntax. Nevertheless, the same precautions apply to using the System Policy Editor as apply to using the Registry Editor, though it is more difficult to make a mistake using the System Policy Editor, because it does not offer control of as many settings as the Registry Editor. Using the appropriate CD, you can install the System Policy Editor from one of the following directories:

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