Repair Windows Registry

Who ever, be it the software, hardware, the users, or who uses the resources of the system will have to register itself and all its settings with the operating system. Every operating system has a method to store this registration information in it. MS Windows operating system stores the information in form of registry files. These files can be multiple in numbers, differing in the information being stored in them. Window registry files contains information about installed software, existing hardware, new hardware added security settings, default Windows settings, information about users, user personal settings, ports used, etc. The registry files, the information stored, the way they are accessed and read has changed with the evolution of operating system from Windows 3.1 to windows 7.

Windows Registry in Earlier Versions of Windows

Windows 3.1 had registry files just to store configuration settings of the COM based application programs. The information was stored in the form of .INI files. Window 98 removed many of the .INI files and introduced User.dat and System.dat. The Millennium edition of windows- Windows ME, added one more registry file – Classes.dat. Windows NT and operating systems based on it, like Windows 2000, Windows XP, etc. store the registry information in files NTUSER.DAT, USRCLASS.DAT, SAM, SECURITY, SOFTWARE and SYSTEM. These files are organized into a centralized hierarchical database called ‘Windows Registry’. It is called database because some of the features of database, like atomicity is followed by it.

Registry Key and Registry Value

A registry entry is combination of ‘Key’ and ‘Value’. Keys are same like folders in Windows. They can have sub-keys, and their reference is like the path in the windows. For example, if Stellar Phoenix Deleted E-mail Recovery software is installed, then the key can be like HKEY_CURRENT_USER\Software\Stellar Information System Ltd.\Stellar Phoenix Deleted E-mail Recovery. The ‘Values’ stored in the key has two parts- ‘Name’ and ‘Data’. Name can contain backslashes but it should be avoided. Each value stored in the key has a data type. There are six root keys, that can have sub keys and these sub keys can have as many sub keys as per needed.

HKEY_CLASSES_ROOT: This key has sub keys that store data of registered applications, file associations, and OLE object class IDs. These data ensure that when a program is executed then the right program is executed.
HKEY_CURRENT_USER: This key stores information and settings of the current user. These settings include the screen color, background image, and many other personal settings.
HKEY_LOCAL_MACHINE: This key contains configuration data about the computer. The registry files that store this information are SAM, SYSTEM, SECURITY, and SOFTWARE.
HKEY_USERS: This key contains data about all the users that are created on that system.
HKEY_CURRENT_CONFIG: This key contains hardware configuration of the local computer that is used by the operating system while booting. The files that store this information are SYSTEM and NTUSER.dat.
HKEY_DYN_DATA: This key is only available in Windows 95/98/ME. This contains information about hardware, plug play devices, and their configuration. The data is not persistent but is created after booting and destroyed on turned off.

The value stored in the keys is divided in two parts, ‘Name’ and ‘Data’. The Name can contain ‘’ character, and Data should confer with the allowed data types. The data types of the values stored in the key can be any of the following.

REG_NONE: No type
REG_SZ: A string value type
REG_EXPAND_SZ: An expandable string value that can contain environment variables
REG_BINARY: Binary data
REG_DWORD / REG_DWORD_LITTLE_ENDIAN: An integer between 0 and 4,294,967,295
REG_DWORD_BIG_ENDIAN: An integer between 0 and 4,294,967,295.
REG_LINK: symbolic link
REG_MULTI_SZ: An array of unique strings
REG_RESOURCE_LIST: Resource list
REG_FULL_RESOURCE_DESCRIPTOR: Resource descriptor
REG_RESOURCE_REQUIREMENTS_LIST: Resource requirements list
REG_QWORD / REG_QWORD_LITTLE_ENDIAN: A 64-bit integer that was introduced in Windows 2000

Cause of Registry Key Corruption

The information in the registry files is needed by the computer from the time it boots, until it is turned off. If the registry files are corrupted then user can face various problems while operating the computer. Various reasons for registry damage can be improper shutting down, power fluctuation, or install/uninstall of an application.

Improper Shutdown/Power Fluctuation: When the computer is in running state, it keeps record of all the changes made in registry. These changes are finally written in the system registry file when the system is being turned off. When the computer is turned off improperly due to power fluctuation/failure, or intentionally by the user, the final registry changes are not saved. This leads to wrong entries in the registry. Corrupt registry files can stop the operating system from working properly.
Improper Uninstall: During uninstall process, it may be possible that some of the registry information is not deleted, or it may be possible that some information is left in some other user account. The ‘Orphan Keys’ left behind in the windows registry can slow other programs while starting. And also, the place occupied by the registry key is left void after uninstalling the hardware/software making the system slower.
Improper Re-install: When software is installed again after removing it. Then duplicate or multiple entries of the software can be written in the registry file. This can cause inconsistency in the entries causing the software to run slowly or not run at all.
Virus/Malware/Spyware: People with malicious intention can try to damage your system be sending Virus, Trojan or any other spying programs. These programs can steal the registry entries, duplicate them, add new undeletable entries, corrupt them, or even delete them.

All these situations can cause improper functioning of the computer system. To cope up with this situation there are many methods which can be done manually, or with help of tools.

Recommended Software to Repair Windows Registry Errors

Many companies have launched registry managers in the market that can repair and fix errors in Windows registry in no time. Most recommended option is the Stellar Phoenix Registry Manager.

Stellar Phoenix Registry Manager to Repair Windows Registry Errors

This application developed by Stellar Information System Ltd. is a bundled offer .Option to secure erase hard disk and files and repair Windows registry errors is one of the many functions included in it. The software fixes all the invalid entries in the Windows registry. Stellar Phoenix Registry Manager not only repairs registry entries but also secure erase files and folders.

Secure erase option permanently deletes the files and folders very easily using powerful algorithms so that they are unrecoverable by any means. It has more than 10 algorithms, having up to 35 passes, to erase data. This software can also delete data permanently remembered by the web browsers, installed applications, and other left over traces in the computer. Stellar Phoenix Registry Manager not only erase and fix the registry entries but can also take its backup and restore the backup when needed. Moreover, an application schedule can be set so that operation can be performed at a preset time.

Stellar Phoenix Registry Manager is recommended software to repair Windows registry errors. For more information, visit http://www.stellarinfo.com/data-safety-eraser/registry-manager/registry-cleaner.php.

Manual Methods to Repair Windows Registry Errors

Manual procedures include editing the registry information and taking backup of the registry.

Editing: Windows provides ‘regedit.exe’ application to read and edit the registry. Many also provide Regedit32.exe, but it is know just a stub to evoke Regedit.exe. The editor can read, create, edit, and delete the entries in the registry. It can also be used to grant registry permissions to other users by the administrator.
To edit the registry, click on the ‘Run’ option in the ‘Start’ menu. Write ‘regedit’ and click OK. This will start the editor. Right-click on the names under the Name column, and choose to rename, modify, or delete the key-value. Right click on the left pane to create new keys in the opened key hierarchy.
Store Backup: Registry editor provides options to store backup of whole registry or partially of some keys. In the registry editor, click on ‘File’ menu in the registry editor and click on ‘Save’ to store in form of .REG files. These file are text files saved in the hard disk that can be imported by the system at any point of time. You can also make changes in the file to create new key, delete key, and key value to create a new registry. Data is stored in the REG file as:
Hive NameKey NameSub key Name
Value Name=Value type: Value data
Add (-) sign before key name (- HKEY_CURRENT_USER\Software) to delete that key. You can add new values to keys by writing new values down the older values. Delete values by writing a (-) sign after = in the value name.
Backup facility of windows: This is a backup utility that backup registry files along with other important system files. To open this, Click ‘Start’ and move to ‘All Programs→ Accessories → System Tools → Back Up’. Click on the ‘Advance Mode’ link in the starting screen. Click ‘Backup’ tab in the Backup application. Choose ‘System State’ in the directory and click ‘Start Backup’ button. A copy of registry files will be saved. Directly click on this saved file to restore when needed. To backup the system state through DOS prompt write the command, ‘ntbackup backup systemstate bks file’ name on the prompt. The file is to be created in the GUI version of ntbackup.exe utility. There are various parameters available for this command. Window registry will be saved along with the system state backup which can be used to restore at a later stage.
Restore Backup: Click on the File menu in the registry editor and click on the ‘Import’ option to import saved registry. To import a backed up registry file through DOS prompt type regedit.exe /s file name on the prompt.
Other Options: There are many more application APIs like, RegCloseKey, RegCreateKey, RegSaveKey, RegLoadKey, etc., that can help in editing registry files. Other than these methods, ‘Boot from Last Known Good Configuration’ option is also helpful in restoring to a good registry state during problematic times. There is also a ‘policy’ option in the registry files that restricts users, who do not have administrative privilege, to make changes in the window registry.

Along with all these windows options there are many third party registry applications available for editing, storing, restoring, repairing, and cleaning. In spite of some added complexities like these, the database-like feature of windows registry has standardized the registry data. The data is more typed, atomic, categorized, and easily backed up. Also, the registry is accessible from a remote position due to this centralized structure. In spite of all these, installation, un-installation, and repair of registry had become complicated.