The configuration database in all versions of Windows starting with Windows 95. The Registry contains settings for the hardware, system software and applications in the PC. It comprises the SYSTEM.DAT and USER.DAT files, and there are separate Registry entries for the 32-bit and 64-bit versions of Windows. A PC with many applications can easily have a hundred thousand or more entries in the Registry.
In the earlier Windows 3.x versions, the Registry database held certain system components, and all other system settings were stored in regular files (see WIN.INI
The Registry can be edited directly; however, that is usually only done for very technical enhancements or as a last resort. Routine access to the hardware and software configuration is done via the Control Panels and Properties menus. Right clicking almost every icon in Windows displays the Properties menu for that object. See Win Registry
and Registry cleaner