The Windows Registry is a database that stores operating system and application software settings and options. It is accessed with the program Registry Editor (regedit.exe).

Prior to its use, Microsoft used a text based "INI" file for each program installed to keep track of the programs' settings and options. The Windows Registry is meant to be a centralized repository of all the settings, configuration, and options for each and every program and for each and every computer user.

Since the Windows Registry contains settings and configurations of almost all programs installed in the computer, including the operating system itself, the Windows Registry is one of the main target of most viruses including spywares and malwares. Viruses usually modify the Windows Registry to automatically load their components. They also modify the Registry to hide their presense and do their malicious work.

 They also modify the Registry to hide their presense and do their malicious work.

On the positive side, the Windows Registry is the key to certain advanced program enhancements not normally accessible to ordinary users. For example, your browser, the Internet Explorer lets you change the configuration thru "Internet Options" on the "Tools" menu. You can change your homepage; change your security, privacy, and content settings; change advanced settings like accessibility and others. But how do you change the MTU? MTU stands for Maximum Transmission Unit. Techies who know what it is know that changing its default value may lead to faster internet browsing. But how do you change it? It is not included in "Internet Options". That is when editing the Registry is necessary. With the Registry Editor you can manually change the value of the MTU if you know where it is located in the Windows Registry.

A word of caution to those who want to work manually with the Windows Registry, MAKE SURE YOU KNOW WHAT YOU ARE DOING. Inadvertent modification of the Windows system configurations and settings in the Windows Registry CAN make Windows XP unstable or totally become unbootable.  But this warning should not make you afraid of working with the Windows Registry.  There are steps you can make to guarantee that you revert any change the you make on the Windows Registry.  First of all, you may use the System Restore utility.  Also you if you are going to change a key or a value in the Registry, you may save them prior to any changes so that you may be able to rollback any change that you make.

The Windows Registry has five sections as shown by Figure 1 below, namely: HKEY_CLASSES_ROOT, HKEY_CURRENT_USER, HKEY_LOCAL_MACHINE, HKEY_USERS, and HKEY_CURRENT_CONFIG which are sometimes referred to as hives.

HKEY_CLASSES_ROOT, abbreviated as HKCR, stores informations about files and their file associations.

HKEY_CURRENT_USER, abbreviated as HKCU, stores setting about the currently logged-in user.

HKEY_LOCAL_MACHINE, abbreviated as HKLM, contains information on the current local machine.

HKEY_USERS, abbreviated as HKU, contains subkeys corresponding to the HKEY_CURRENT_USER keys for each user profile actively loaded on the machine

Windows System Registry Explained - The Windows System Registry is a Microsoft Windows OS component that started to exist since Windows 95. Microsoft continued to embed it on its later versions. The Registry stores necessary information of all components installed on the Windows-based machine. These components include its hardware and software resources.

Why is it Necessary to use Windows XP Registry Cleaner - Registry is the most significant component of Microsoft Windows XP operating system, which contains information regarding operating system and all the applications that are installed and running on it. It is the fundamental component, which is refereed by the operating system for recognizing application data and permissions related to particular application.

How to Distinguish Good Registry Cleaners from Bad Ones - Users may utilize the functionality of registry cleaners to remove invalid entries and possible malware threats from the Windows System Registry to improve their machine's overall performance. Instead of manually modifying and changing System Registry values to correct certain errors in a computer system, users can reduce the workload by using registry cleaners downloadable from the Internet.