The registry is the most important component of the Windows system. It stores information that is necessary to configure the operating system, such as user profiles, applications and devices. The registry also stores information about uninstalled programs if they were uninstalled incorrectly, parameters that were left behind after the uninstall process, and references to deleted files. In the course of time, the registry accumulates more and more redundant data that slows down registry access and causes system performance loss.

Although it is not recommended to edit the registry manually, there are situations when a registry editor is absolutely necessary. For this, you can use various programs (Regedit.exe or Regedt32.exe), group and system policies, registry files, or special scripts (for example, scripts written in VisualBasic).

As we said before, the registry stores a great amount of information, including profiles of all users, information on installed applications and types of documents that can be created by each program, information on folder properties and application shortcuts, installed hardware and ports that are used.

Because the Windows registry is a complex relational database, all information that can be stored in the resulting information containers of this database (values), must be strictly classified. Values are classified by a data type, which represents the specific kind of data that the value can store. Overall, there are 11 types of data.

As we said before, the registry is a hierarchical database where information is presented on a number of levels (up to 6). Hive keys are on the first level.

The Microsoft Computer Dictionary defines the registry as a central hierarchical database used in the Microsoft operating systems starting with Microsoft Windows 98. The database stores information that is necessary to configure the system for users, applications and hardware devices.