The Structure of Your Windows Registry

...or Climbing the Windows Regis-Tree

Note: Before reading this article, you may first wish to read What Is My Windows Registry, anyway?

This article is aimed at those of you wishing to know a bit more about the structure of your Windows Registry before diving in - alone or with a software product - to alter it in any way. As our article entitled Caution: What You Must Know Before Starting Any Windows Registry Repair warns, while registry repair can prove to be an incredible performance enhancer, it can also severely damage your system if handled improperly.

You need not necessarily know all the Keys and Sections in your registry in order to satisfactorily perform Windows registry cleaning and registry repair - certainly not with the Wizard-like aid of all the registry repair software products on the market (including those we've reviewed), but it can't hurt to know what you're dealing with. So, if you're game for a little jargon deciphering, here you go...

A Windows registry is a database - which, as you must know by now is a repository for data. Data in a registry is stored in what's known as a tree structure. Picture a family tree in genealogy and you have a good idea of what we're talking about. This is a hierarchical structure (akin to the paternalistic / maternalistic lineages in a family tree).

The tree structure is often called an inverted tree because it's usually drawn with the root at the top. The branches connect nodes, each node containing a key. We'll now spend a bit of time here with keys, because it is to them that every application in your PC must refer when performing its operations.

With your keys out of whack, your system will not operate properly. Period.

One way to describe a key is as a field that your computer uses to sort data. More plainly put, a key is a directory of files, or a big, fat, well-organized and well-labeled folder.

Beneath the nodes on your tree (inside they keys) are leaves. These leaves are either subkeys or the data files (also called entries or values) stored in the directory.

You can view the values contained in any key in your registry by simply open Windows Registry Editor and highlight the key in the left pane. The values will all appear in the right pane. What they all mean (and what they all do) is a more involved matter.

(Incidentally, you may have to click on '+' to expand a "collapsed" key and find out what subkeys and/or values it contains. Whenever you see a '+' sign, that means more information is to be found by clicking on it.)

There are 5 top-tier keys that form the foundation of your Windows registry:

• HKEY_CLASSES_ROOT: stores information on file types and applications that are "object linking and embedding" aware; this is where your computer goes to match a file to its corresponding application

• HKEY_USERS: contains all the information (like Preferences data) on each user on the system.

• HKEY_CURRENT_USER: is where the computer finds all the data relating to the PC's current, active user - at the moment, you; this key obtains this data as it needs it from the HKEY_USERS key.

• HKEY_LOCAL_MACHINE: holds all the data on all the hardware and software installed on the machine, divided into 5 subkeys:
  
  1. Hardware - stores settings for device drivers and such; recreates itself each time you reboot; cannot be modified
  
  2. Software - stores all data on installed software
  
  3. Security - stores data on all security policies (ie passwords, account lockouts, user rights, etc.); cannot be modified
  
  4. Security Accounts Management (SAM) - stores data on user accounts, security settings, group memberships, etc.; cannot be modified
  
  5. System - stores info related to booting up the system

• HKEY_CURRENT_CONFIG: contains all the necessary configuration data pertaining to currently active hardware and software; obtains its data from the HKEY_LOCAL_MACHINE key as it needs it.

This, in a nutshell, is how your PC manages itself.

Now that you've got a better understanding of your computer's filing system, consider one of the software solutions we've reviewed on this website for helping to keep those files neat, orderly, efficient, and up to date.