What is Windows Registry?
The registry is a database in Windows that contains important information about system hardware, installed programs and settings, and profiles of each of the user accounts on your computer. Windows continually refers to the information in the registry.
For what Windows Registry is used?
The Windows Registry is used to store all settings for the Windows operating systems. This includes settings for software and programs, operating system configuration, hardware configuration, user preference, control panel settings and many more
How Registry is creates?
Programs and applications typically make all the necessary changes automatically. For example, when a program is installed in Windows, a new subkey is added into the Windows Registry which contains settings such as program location, version, other settings which should be enable and disable, how to start the program etc. If you want to make any changes, you should not need to make manual changes to the registry.
How to accessing the Registry:
You can configure Registry using the Registry Editor program, which is access by following method -
- Open the Start Menu.
- Choose "Run".
- Enter "regedit" and press Enter
- Now you see the windows of Registry Editor
In the database of Registry, 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. A key can have any number of values, and the values can be in any form.
A registry tree can be 512 levels deep. You can create up to 32 levels at a time through a single registry API call.
The registry contains 5 root keys, each of which contains specific registry information:
HKEY_CLASSES_ROOT- This key contains file name extension associations and COM class registration information such as ProgIDs, CLSIDs, and IIDs. In simple terms this key contains necessary information to launch application or instruction to do task.
HKEY_CURRENT_USER – This key makes it easier to establish the current user's settings. It contains configuration information for Windows and software specific to the currently logged in user that includes settings of environment variables, data about program groups, , display settings, desktop wallpaper, printers, network connections, and application preferences, keyboard layout etc.
HKEY_LOCAL_MACHINE -Contains computer specific information including installed hardware and software. It contains subkeys that hold current configuration data, including Plug and Play information (which includes a complete list of all hardware that has ever been on the system), network logon preferences, network security information, software-related information (such as server names and the location of the server), and other system information.
HKEY_USERS- Contains user-specific configuration information for all currently active users on the computer. The settings for program, user's choices of themes, colors, desktop and Control Panel settings are stored here as user's profile.
HKEY_CURRENT_CONFIG – Contains information about the current hardware profile of the local computer system.
Backing Up Registry Keys
Before you make changes to the registry, you should always make a backup copy of the key you are about to change.
Do the following:
- Windows 7/Vista: Click Start > Run. Type regedit and press Enter.
- Windows 8: On the Start screen, type regedit and then click on regedit.exe.
- From the menu at the top select File > Export....
- Choose a location on your computer to save the file to.
- Type a name for the registry backup file.
- Click Save
- The entire registry has been backed up.
Restoring to the Registry from a Backup
- If you need to restore the registry to its previous state, you may do so with a registry backup file.
- Locate the registry file you saved to your desktop.
- Double-click on the file.
- Click Yes when asked if you are sure you want to add the information to the registry.
- The registry will immediately revert to the previous settings defined in the registry backup file.
Cleaning the Registry
When you notice a reduction in the operating speed of your computer, repeated freezes or taking a longtime to startup, you can take the indication that you need to clean Registry.
As we see above a registry may have thousands of entries, and new entries are created all the time. As it fills with information, the registry may cause a computer's performance to suffer. One problem is that Windows almost never removes registry entries, even if a program is uninstalled, as most uninstallers aren't able to effectively remove their own registry keys. Due to this the registry can be cleaned up. But manually cleaning it up effectively isn't easy. There are many programs that do wonderful job to clean the Registry automatically.
But it is always advisable to take backup of Registry before cleaning.