What is Registry? Registry is a database where Windows stores all types of settings and option related information, in other word, it consists of all information regarding hardware, software, users etc. Now, in place of Win 95 or 98, registry was build up with two hidden files - USER.DAT & SYSTEM.DAT, but now it consists with another file. Named CLASSES.DAT The structure of registry Registry is a Hierarchical Structure, just like our disk’s directory tree or Windows explorer. Now if we run the registry editor (Start -> Run -> Regedit), then we will find six main braches, called HIVE. Each hives contains some keys, now every key contains some subkey or value. This value stores all the information in the Registry! All The Six Hives Of Registry. 1. HKEY_CLASSES_ROOT – It contains all the information related to File Association, OLE and Windows Shorten. 2. HKEY_CURRENT_USER – It consists of all the information for a particular active user who is in log on condition, e.g, logon names, desktop settings or start up menu etc. 3. HKEY_LOCAL_MACHINE – This hive contains all hardware and software related information. 4. HKEY_USERS – It contains all information related to users. For every user, there exists a SID subkey. 5. HKEY_CURRENT_CONFIG – It stores hardware configuration setting related information of current user related to HKEY_LOCAL_MACHINE. 6. HKEY_DYN_DATA – It stores all information about plug-n-play devices. Every registry value contains 5 ata types – REG_BINARY – Here data gathered in Raw binary format, basically it contains binary data related to Hardware component. REG_DWORD – Here data stored in as byte number. It consists boolesn values e.g, ‘0’ or Disable and ‘1’ or Enable. REG_MULTI_SZ – Here data stores as multiple string and null character separates each other data. REG_SZ – Here data stored as simple readable text in standard string form. EDITING THE REGISTRY If you open the registry editor you will find a simple ecplorer type window. Which consists of two parts, left side is called Navigation Pane, here we can find all the hives with + and – signs. If we click + sign, the hive will expand and all the key and subkeys will be displayed. And at the right side we will find the values of the key. To change any value of any key, just double click on it and if you want to delete it, simple right click on it and select delete. Related to this thing, you can view my this previous article Some Important Registry Editing! 1. How to know System BIOS information? Find the key HKEY_LOCAL_MACHINE/HARDWARE/DESCRIPTION/System Now, at the right side you’ll see some keys, among them, view specified keys- SystemBiosDate, SystemBiosVersion, etc. 2. How to know full information of your processor? Find the key HKEY_LOCAL_MACHINE/HARDWARE/DESCRIPTION/System/Central/Processor/O Under this hive, you will see many keys, check all these keys to know your processor information! But do not modify it! Some times you’ll find values in Hexadecimal system, in that case, simply switch to decimal mode! 3. How to disable Autorun feature on Windows? Find the key HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\NoDriveTypeAutorun Please follow the codes Code: Value Meaning 0x1 or 0x80 Disables AutoRun on drives of unknown type 0x4 Disables AutoRun on removable drives 0x8 Disables AutoRun on fixed drives 0x10 Disables AutoRun on network drives 0x20 Disables AutoRun on CD-ROM drives 0x40 Disables AutoRun on RAM disks 0Xff Disables AutoRun on all kinds of drives Default Values Code: Value Operating System 0x91 Windows Server 2008 and Windows Vista 0x95 Windows Server 2003 0x91 Windows XP 0x95 Windows 2000 That’s All About Registry And Registry Editing! While editing the registry, don’t forget to make restore point, because wrong editing of registry may crash your Windows! Be Careful and Enjoy!