For many computer users the Microsoft Windows registry can be a very intimidating place. Scary stories of computers becoming broken or data being lost from one simple Windows registry edit deter most people from the idea of even looking at it. The truth is, with proper knowledge the registry can be easy to navigate and understand. This knowledge can let you get a better view of how your computer functions and also help you learn about windows registry backups and how to fix windows registry errors safely.
What is Windows Registry?
Think of the Windows registry as a giant database, or directory that stores information about your computer. Your operating system, Microsoft Windows, needs a lot of different types of data to start up and run correctly. Instead of storing all of this data in various files throughout the computer, Microsoft decided to have a centralized location where all of this data can be stored and retrieved from. The information you’ll find in the Windows registry is of a wide range. You can find some basic user preferences, such as the screen saver or desktop background. In contrast, you can find more complex settings, like which drivers are installed for your computer’s hardware.
The Registry’s Structure
The structure of the Windows registry is a hierarchy made up of keys and values. At the top level you have root keys (also called “hives”), which are like categories. These categories represent different types of information stored in the registry. Windows 95, 98 and ME all have 6 root keys, whereas every version above that has 5. The root keys that you will find in the registry are:
- HKEY_LOCAL_MACHINE: Information stored here is very technical. Here is where all of the hardware data for your computer is stored, such as system memory and operating system data. Data here stays the same regardless of which user is logged in.
- HKEY_CURRENT_CONFIG: The data stored here is the configuration information for your computer’s hardware. This is linked to the HKEY_LOCAL_MACHINE root key.
- HKEY_CLASSES_ROOT: This root key handles all of the file type associations, meaning what programs open files of a certain extension. These are the settings that tell your computer to open a .doc or .txt file with programs such as Microsoft Word.
- HKEY_USERS: Here you will find a list of all the users who have ever logged onto your computer. It also contains settings specific to those users, such as their desktop background or network settings.
- HKEY_CURRENT_USER: This root key holds the settings of HKEY_USER, except only for the current logged in user. This means that the data here will change when a different user logs in to the computer.
- HKEY_DYN_DATA: This root key contains information about hardwired plug and play, and is only found on Windows 95, Windows 98 and Windows ME.
Underneath these root keys you can have subkeys. The best way to imagine this structure is like files and folders on your computer. A root key is like a drive, such as your C drive or your D drive. Inside the root key you can have any number of subkeys, just like on your C drive you have folders such as “Program Files” and “User”. Subkeys can be nested inside of each other multiple times, just like you can do with folders on your computer. For example, inside “User” you have “My Documents” and “My Pictures”. Likewise, you can create a number of folders inside of “My Pictures” for each type of picture. Keys in the registry work in this same fashion. At the very end, you have values; just like in your “My Pictures” folder you have an individual file – a picture.
For example, the HKEY_CURRENT_USER root key holds all of your current user settings. If you want to change the font for the icons on my computer, you would go to the “Control Panel” subkey. Under there, you can navigate to the “Desktop” subkey. Here there are a number of subkeys listed, such as “IconSpacing”, “MenuHeight” and “IconFont”, just as was looked for. The “IconFont” key contains a value – the font that is used for desktop icons.
How to Use the Registry
Now that you know how to navigate the registry, where is it? Before venturing into the Windows registry, it’s important to understand why so many people are warned against it. The registry contains very sensitive configuration that keeps your computer running. One wrong windows registry edit can corrupt it, causing your computer to no longer function without some serious windows registry repair. Before you change windows registry, see if any configurations you need to do can be done from the Windows interface. If you still need to make a windows registry edit, be sure to make windows registry backups as a precaution.
The Windows registry is stored in two files on your computer called “system.dat” and “user.dat”. These files are stored in “C:\Windows”, but are hidden by default. To show the hidden files, from your menu click “View”, then “Folder Options”. From here click on the “View” tab and select “Show All Files”. Now, under “C:\Windows” you should see the two files. You’ll also notice a “Profiles” folder. In here you will find a folder for each user on your computer, with their own “user.dat” file. The first “user.dat” file that you saw, in the “C:\Windows” folder stores the default settings for a new user.
Viewing the registry is not as simple as opening these files. Instead you need a Windows registry editor. Luckily, a Windows registry editor comes preinstalled with Windows. This is a basic editor that lets you perform tasks such as adding or removing keys and values, and exporting and importing sections of the registry.
To use the Windows registry editor, or REGEDIT, click on your “Start” button. Select “Run” and type “REGEDIT”, then click OK. Before going further it’s suggested that you perform windows registry backups by choosing “Export Registry” from the Registry menu. If you know what section you are going to change, then you can choose to export just that section, or “branch”. Once you’ve done this, you can begin navigating through the registry. Select the entry that you want to change by navigating through the keys, starting with the “HKEY” root keys. When you get to a value that you want to change, right-click on that value and select “Modify”. You can change the value in the “Value Data” box, then click OK.
Removing something from the registry is just as easy as modifying it. Start by performing windows registry backups as you did before. Navigate through the keys of the registry to the value you would like to change. Once you find it, press the delete key or right-click on the value and choose “Delete”. If you can’t find the value you’re looking for, you can search the registry for a specific word. To do this, go to the Edit menu and click “Find”. Type in the word or filename that you’re looking for and then choose “Next”. The first item displayed is the first occurrence that REGEDIT could find. If you would like to see the next occurrence, press the F3 button on your keyboard.
When you understand the structure and purpose of the Windows registry it becomes much less intimidating. Regardless, it’s always important to be cautious when modifying or removing items from the registry. One seemingly innocent windows registry edit can make your computer unstable, or worse. For beginners to windows registry repair, it’s best to become as familiar with it as possible and learn all the necessary precautionary steps before attempting to change windows registry yourself. Try the resources below if you’d like to learn more on Windows registry repair and use.
- TechNet: The Windows Registry
- Windows Registry Information for Advanced Users
- In Windows, What is the Registry?
- The Windows NT Registry
- How to Clean Your Windows Registry and Speed Up Your PC
- The Windows Registry — Learning & Scholarly Technologies
- Windows XP Hacks: Don’t Fear the Registry
- Forensic Analysis of the Windows Registry (PDF)