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Registry Editing

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The Registry is the key to getting Windows to work the way you want. We show you how to unlock it safely. It’s at the heart of how your programs and settings work in Windows. Editing the keys in the Registry is the key to tweaking Windows. Any configuration utility you install just gives you a friendly front end to editing the most useful keys, but if you know what you’re doing it’s faster to make the changes in the Registry Editor (Start, Run, REGEDIT) directly. To change a key in the Registry Editor just double-click it. It usually takes longer to find the key you want in the tree, so if you expect to edit a key often save it as a Favorite so you can get back to it quickly.

What’s where?
Windows 95 replaced the various INI files that stored system information with a database. It’s still stored in multiple files, but the Registry Editor enables you to see all the settings in one place. The files and the structure change with each version of Windows, but for compatibility older keys are always stored in the same place.

HKEY_CLASSES_ROOT stores file associations and related information. HKEY_USERS stores the individual preferences for all the users on your PC – this is mostly the contents of USER.DAT. HKEY_CURRENT_USER is just the section of HKEY_USERS for whoever’s using the PC at the time. HKEY_LOCAL_MACHINE stores information about hardware, software and preferences from SYSTEM.DAT. and HKEY_CURRENT_CONFIG links to the section of HKEY_LOCAL_MACHINE for the current hardware configuration – primarily mainly graphics card and printer settings.

Each root key is a hierarchical branch of keys and sub-keys. Both keys and sub-keys contain values which is where the settings are. Each value has a name and the value might be text, raw binary data or a DWORD, which is a number (often 0 for off or 1 for on).

In Windows 98 the Registry is stored in just two files in the Windows folder: SYSTEM.DAT and USER.DAT. You can take copies of these files yourself but Windows 98 backs up the Registry at start up once a day and by default keeps the last five working copies as numbered files called RB00x.CAB in the hidden SYSBCKUP subdirectory inside the Windows folder. If you want to keep more than five copies, edit the C:\WINDOWS\SCANREG.INI file and change the value for MaxBackupCopies.

You can save the Registry backups into a different file by adding a folder to the BackupDirectory line like BackupDirectory=C:\BACKUP, but it’s safest to leave the files where Windows can find them. If you want to backup other system files at the same time you can add them to SCANREG.INI as Files=[folder code],[file name]. Instead of giving the path to the file type a folder code: 10 for WINDOWS, 11 for WINDOWS\SYSTEM and 30 for C:\, followed by the file name. For example, to back up C:\BOOTLOG.TXT and the WinZip history file you’d include the following line: Files=30,BOOTLOG.TXT,WINZIP.LOG.

If you’re making changes to the Registry, take a backup yourself first: click Start, Run and type SCANREGW to run the Windows Registry Checker. This checks the Registry for errors and assuming there aren’t any asks if you want to back up the Registry again. If you want to force Windows to check and back up the Registry every time you boot, choose Start, Run, Regedit, find the HKEY_LOCAL_MACHINE\ Software\Microsoft\Windows\ CurrentVersion\Run key and create a new String value called RegistryChecker with the value SCANREGW.EXE /AUTORUN.

If there’s a problem with the Registry when you boot up Windows, the Registry Checker replaces it with the most recent back-up copy. You can also force it to use an older version of the Registry by pressing [F8] while Windows is booting, choosing Safe Mode Command Prompt and running SCANREG/RESTORE to choose which backup to use.
Cleaning the Registry
It’s not unusual for one program to create 100 or more keys in the Registry, and Windows has plenty of keys of its own. The Registry ends up as a large set of files. That leaves you with a huge file filling system memory and as you install and uninstall applications the Registry becomes fragmented, and Windows slows down even more while it waits for keys to load. If you’re using an earlier version of Windows then cleaning out unnecessary Registry keys can boost performance.

Never delete a Registry key unless you know what it does, and always take a backup of the key first, just in case. Rather than looking for old keys yourself, download a Registry cleaner like the excellent, free RegCleaner ( This shows you orphan files and software that has keys in the Registry, so you can delete all the keys for packages you’ve uninstalled. In Windows 98 you can compress the Registry afterwards. Restart in MS-DOS mode and run SCANREG /OPT to remove unused space and shrink the files. Spend half an hour spring cleaning your Registry and your whole PC will feel the benefit.
Power Registry Editing with TCD Reg

Finding the keys you want and comparing with your backups is much simpler in this Registry tool

The Registry Editor enables you to look in keys, values or data, but with TCD you can also search just a section of the Registry, use wildcards and replace as well as find.

When you want to edit several keys, you can pick them from the search results by ticking the checkboxes and then change them all at once.

Instead of using the menu commands, you can just right-click a key to add it to the drop-down list of bookmarks.
Top Registry tools
The Registry Editor isn’t the most powerful of tools: try these shareware and freeware utilities to make life easier

You don’t have to open the Registry at all if you search with the Registry Toolkit ( You can search and replace using regular expressions, undo edits and see what changes a .REG file will make before you import it. If you’re happy with the Registry Editor, you can add a drop-down history bar to it with the free RegEditX ( so it’s easier to get back to keys you’ve edited before.

A ghostly affair

If there are a couple of keys you often change, use the JumpReg tool in the 12Ghosts utility pack ( to open those keys in Registry Editor from an icon in your System Tray. You can also jump straight to a key you’ve copied into the clipboard. RegCrawler ( also adds keys to a System Tray icon as bookmarks. It’s much faster at searching than the Registry Editor and you can change multiple keys at once Try another Registry editor with more features: the TDC Registry Suite ( includes two programs, Reg the editor and Regback, for taking regular, scheduled backups. Reg has much more powerful search and replace options and you can hide keys and sub-keys that you’re not interested in. Hover over a value name to see what kind of key it is, then right-click in the empty space. Reg offers you all five kinds of keys, not just the three in the Windows Registry Editor. You can also view the current Registry and your backup together to compare keys. Online help

It’s easy to find common Registry keys in the Microsoft Knowledge Base or on Web sites like the Windows Registry Guide (, but if you can’t easily spot the keys you need, you can always use the free RegMon utility ( to find out what keys a setting or application is accessing.
Track down your Registry keys

RegMon shows you how many Registry calls Windows makes every second and it helps you find the keys you’re interested in

The flood of keys in RegMon looks pretty confusing. Use [Ctrl] + [E] to stop data capture and [Ctrl] + [X] to clear the screen until you’re ready to run the task that you’re want the Registry keys for.

Choose Options, Filter/Highlight and trim down the results. Specify root keys or programs that you’re watching (Include) or very interested in (Highlight) and the ones you want to ignore (exclude).

Clear the RegMon display and run the program or command that you want to find the Registry keys for. You’ll see the ones that fit your filters appear in RegMon with highlights on matching keys.

You can use wildcards for complex pattern matching to help you find specific Registry keys used by particular applications. Lexplore*google will find all keys and values for Internet Explorer’s Google toolbar.

You can go back and add highlights to keys that RegMon has already captured – or you can search through all the keys if highlighting is matching too many keys.

Once you find the Registry key that you’re interested in, double-click it or click the Registry Jump button on the toolbar to go straight to that key in the Registry (and remember to bookmark it for later).
This material is the copyright material of or licensed to Future Publishing Limited, a Future Network plc group company, UK 2004. All rights reserved.
This material is the copyright material of or licensed to Future Publishing Limited, a Future Network plc group company, UK 2004. All rights reserved.

Article ID: 835818 - Last Review: 07/08/2008 13:51:11 - Revision: 3.4

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