Starting with Windows 95, the Registry is a hierarchical database that holds configuration data about the hardware environment of the PC, Windows itself and installed applications. The Registry can be edited directly, but that is usually done only for non-published tweaks or as a last resort. Routine access to configuration settings is done via the Windows control panels and Properties menus. See Win Control panels and Win Properties.
Registry DetailsTo get into the Registry, run the Registry Editor program (REGEDIT.EXE) from the Run command in the Start menu. The Registry contains the following five "keys," which function like folders. Each key has a "subkey" that contains the configuration values.HKEY_CLASSES_ROOTContains file associations and OLE information. It shows exactly the same thing as the folder HKEY_LOCAL_MACHINE\Software\Classes.HKEY_CURRENT_USERThe portion of HKEY_USERS that pertains to the current user. It contains the colors, fonts and attributes for the desktop environment as well as any network connections. If the current user is the only user of the system, HKEY_CURRENT_USER and HKEY_USERS are the same.HKEY_USERSContains the above information for all users of the system.HKEY_LOCAL_MACHINEHolds a large number of settings for the hardware, system software and applications. Install programs create their own subkeys and values within this key. Older applications may use the INI files that were introduced in Windows 3.x, rather than the Registry.HKEY_CURRENT_CONFIGURATIONContains settings for the current display resolution and printers.HKEY_DYN_DATA (Windows 95/98 Only)Holds performance statistics that can be viewed with System Monitor (SYSMON.EXE).