NWA-PCUG Newsletter Article
The Windows Registry Demystified
by Dale Oliver, President, April 2002
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The Windows registry can be thought of as a repository of information relating to just about everything about your computer, including the operating system, installed software programs, user preferences and settings, file locations, drivers, hardware, etc. Virtually everything about how your system operates can be controlled through the registry. Registry settings can even cause your computer to run very slowly and inefficiently, or run very quickly and efficiently.

The Windows registry first appeared in Windows 3.1. It was much simpler then, consisted of a single file named REG.DAT, and had only a limited scope compared to the modern Windows registry. Windows 9x versions of registries touch virtually every detail of how the system operates, and are comprised of two files found in the \WINDOWS directory: SYSTEM.DAT and USER.DAT. Windows NT registries are spread over a number of files (called hives).

The registry can be easily modified, and is far less mysterious than the average user is lead to believe. If you are comfortable changing preferences in programs, such as setting the default font or file locations in your word processing program, for example, then you should feel comfortable changing the settings in the Windows registry.

Always follow this procedure when making changes to the registry:

1. Backup the registry first.
2. Make the desired changes to the registry.
3. Test the changes thoroughly.
4. Restore the registry if you notice any new or unexplainable problems.
5. Delete the old backup after a period of time (a week or two) of problem-free use.

How to easily backup the registry:

1. Click Start > Run (or press the Window key, then R).
2. Type "regedit" without the quotes and press Enter.
3. Make sure My Computer is highlighted in the upper left of the registry tree window.
4. Click Registry > Export Registry File from the main menu.
5. Name the export file and click the Save button.

To easily restore the registry:

Double-click the desired registry backup file you saved using the above procedure.

This process is actually better than manually copying the registry files since the registry files are constantly open whenever Windows is running, so they must be copied from a DOS prompt after resetting their attributes from hidden, system, read-only prior to copying. Additionally, using Regedit allows you to select only the particular registry keys you want to export, which can be very handy if you only want to fiddle with limited parts of the registry, and not restore the entire registry contents to "undo" any changes you've made.

The items that appear as folders in the left pane of the Registry Editor window are known as "keys" and the contents of these keys are called "values." Much like the arrangement of folders organize the files on your hard drive, registry keys can contain other keys as well as multiple values.

Unlike editing a document, changes made to the registry are immediate. You don't manually save the changes. They are instituted the moment you change something in the registry. There is also no "undo" feature in Regedit per se, so you will want to pay attention and not be sloppy if you decide to make changes to the registry. Remember, a current backup of the registry is important in case you goof something up and need to undo your changes.

Windows automatically checks the registry and makes a backup of the existing one when you restart your computer. If the Registry Checker software notices a fairly significant problem, it automatically replaces the registry with the latest known good backup copy. Registry Checker does not, however, fix references to missing files or programs. That requires aftermarket software such as FixIt, System Mechanic, and Norton SystemWorks.

Microsoft used to offer a free utility named RegClean to do this, but they have since removed it from their download sites in an effort to "protect users from themselves." You can still find copies at various places around the Web, such as John Woram's site http://www.woram.com/UTILITY.HTM. BEWARE that RegClean does NOT work with all versions of Windows, namely newer versions such as XP and 2000.

Instead of rebooting your computer to run Registry Checker, you can run it manually. Go to Start > Programs > Accessories > System Tools > System Information. From the System Information main menu, select Registry Checker.

The System Information software provides a powerful set of tools for looking at many of the inner workings of your system. For example, from the left pane, select Software Environment > Startup Programs to see all the "stuff" that runs when your computer starts. And you wonder why your computer takes so long to boot up!

Another nice tool within the System Information program is the system configuration manager. From the main menu, select Tools > System Configuration Utility. Notice that you can do neat things here like the Diagnostic Startup to help with troubleshooting problems when your computer boots up. Also notice the different tabs, including the Startup tab. This allows you to view everything that runs when Windows boots up, and also lets you decide if a particular program should automatically run or not. This can be a powerful troubleshooting aid when you're having problems with Windows booting up.

By default, registry backups created by the Registry Checker are stored in the \Windows\Sysbckup\ folder. This is a "hidden" folder. By default, Windows keeps five separate copies of your registry here, using the names RB001.CAB through RB005.CAB. The oldest file (indicated by the file's time and date stamp, and not necessarily indicated by the filename's sequential number) is replaced by the latest backup. More advanced users can modify the ScanReg.INI file located in the \Windows\ folder to configure a number of specific features relating to registry backups, including the number of backup registry copies to keep. You may want to refer to the article on CAB files at http://pcgroup.nwark.com/vpres- a0.htm to learn more about CAB files.

Simply browsing the contents of the registry without making changes can be a very enlightening experience, and can help you understand a lot about how your system works. However, there are also many very helpful and powerful things you can do by making simple changes to the Windows registry settings.

For a simple example of how you can make Windows suit your needs, one of our club members complained about the scrolling single-column display of available programs in the Windows 98 start menu at a previous meeting. Don't like the way it works? Change it! Go to the registry key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\explorer\Advanced and add the following string value (right-click the Advanced folder, select New > String Value, type in StartMenuScrollPrograms then press Enter). Now right-click the new entry and select Modify. Type false into the Value Data field.

For those of you who like to run Tweak UI, you might find it interesting to know that this software is basically nothing more than a fancy registry editor.

For a very informative article on the Windows registry written in plain English, you may want to read the article at: http://www.itp-journals.com/sasample/E1209.pdf

PC Pitstop http://www.pcpitstop.com and PC 911 http://www.pcnineoneone.com are good sites to help you learn more about your computer and run tests that will suggest ways to improve system performance and reliability.

Having chronic BSOD's (Blue Screen Of Death) and other unexplained errors while using Windows 98? Check out: http://www.pcnineoneone.com/tweaks/fixes1d.html#vxd

WinGuides http://www.winguides.com has good information about how to tune up your PC, tweak the registry to increase system performance and reliability, etc.

An amazing site for information about tweaking the registry and various other parts of Windows to maximize your computer's broadband (DSL/cable modem) connection performance can be found at http://www.speedguide.net/.

Happy tweaking!

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