The registry is a heart and soul of any Operating system. “The computer registry is where all system settings are stored. Whether personal settings or those from an installed application, everything is placed in the registry. Anytime a change is made to your system, the registry is updated to reflect that change. The settings are stored in files, but these files cannot be opened and edited directly. In order to access them you have to open the Registry Editor. From there you can view and make changes.
The registry contains a left and right pane, and everything is arranged in a hierarchy, like Windows Explorer. It consists of three components: keys, subkeys, and values. Collectively these are called hives. The keys are the main categories and are located in the left pane. Below the keys are the subkeys, which may contain more subkeys. When you click on a subkey, the value appears on the right side. Let’s take a look.To open Registry Editor in Windows XP click Start, Run, & type regedit. To open in Vista click start, then type regedit in the “Start Search” text box. It automatically begins to look for the program. After found, it should appear in the area above the text box. Double click the icon.
When the windows appears, notice the main key categories on the left. Each stores certain settings.
- HKEY_CLASSES_ROOT (HKCR): Deals with settings such as shortcuts and file associations.
- HKEY_CURRENT_USER (HKCU): Stores data for the current person who’s logged in. These will change depending on who is using the computer.
- HKEY_LOCAL_MACHINE (HKLM): Contains the settings about a computer’s hardware and software configuration.
- HKEY_USERS (HKU): Stores information about all users that are logged in.
- HKEY_CURRENT_CONFIG (HKCC): Stores hardware information used by the computer at startup.
Double clicking one of the keys will reveal subkeys beneath the main key. Clicking on a subkey will display its value(s) in the right pane. In this example the key HKEY_LOCAL_MACHINE and the Components subkey are selected.
To edit a value, right click the one that needs to be changed and click modify.
Change the value where it says “Value data” and click OK.
Manually editing the computer registry is very dangerous if you don’t know what you’re doing. Making the wrong change can screw up your system. Even if you use a registry cleaning application, you still need to be sure the correct entries are being deleted. If you have any doubts, don’t do it. As far as changing values, it’s very rare if you will have to do so, but make sure you backup your registry before making any changes”.
Structure of the Windows Registry
The registry is a hierarchical database that contains data that is critical for the operation of Windows and the applications and services that run on Windows. The data is structured in a tree format. Each node in the tree is called a key. Each key can contain both subkeys and data entries called values. Sometimes, the presence of a key is all the data that an application requires; other times, an application opens a key and uses the values associated with the key. A key can have any number of values, and the values can be in any form. For more information, see Registry Value Types and Registry Element Size Limits.
Each key has a name consisting of one or more printable characters. Key names are not case sensitive. Key names cannot include the backslash character (\), but any other printable character can be used. Value names and data can include the backslash character.
The name of each subkey is unique with respect to the key that is immediately above it in the hierarchy. Key names are not localized into other languages, although values may be.
The following illustration is an example registry key structure as displayed by the Registry Editor.
Gerard M.B. Pean
Sources: microsoft.com / bukisa.com