Demystifying the Registry

Presentation to Rockland PC User Group January 9, 2007

Deacon David R. Caesar-Dare

Westchester PC Users Group

Presentation Outline

Westchester PC Users Group WPCUG

  • Gathering of folks interested in all aspects of computing

  • Web site:

  • Monthly meeting -1st Thursday

  • Monthly online newsletter

  • 25 workshops – most meet monthly

  • WPC-RENEW – PC refurbishing

  • Telephone support

Registry Mystique

    • Warnings about how editing can be dangerous to your computer:

      • “One false move in the Registry could render your system unbootable.”

      • “Our insurance carrier requires that I warn you that you edit the registry at your own risk.”

  • Only a small percentage of computer users have seen the Registry.

  • There is no icon in the Control Panel or on the Start Menu to access it.

  • Referred to as “one of the most powerful aspects of Windows.”

  • It's the key to absolute power of your operating system.

  • Central repository of information about all aspects of the computer.

  • It is large and its organization often seems to verge on the haphazard.

Why Did You Come Tonight?

  • Hacking the Registry?

  • Tweaking the Registry, i.e., a little hack?

  • Can't imagine going through life without ever seeing your Registry?

  • Just like opening the hood of your car, you may want or need to change a setting that there is no other way to do.

Registry Usage (and you probably didn't even know it)

  • “Loading Your Personal Settings” at startup

  • “Saving Your Personal Settings” at shutdown

  • Changing your wallpaper or screen saver

  • List of recently used documents

  • List of programs and printers

  • Start – Settings – Control Panel

  • Almost everything that tells Windows (and most applications) how to run is stored in the Registry.

  • Knowing a bit about where and how the Registry stores various bits of information makes it less intimidating.

  • Structure and concepts are similar from Win 9x, ME, 2000, NT, XP, but there are differences.

  • Will show mostly XP examples.

  • Will save Windows Vista for another time.

On With the Show

Word of Warning!

  • Can't talk about the Registry without one of these:

  • Looking cannot hurt anything.

  • Changing settings near and dear to Windows in ways that Windows cannot understand will make it inoperable.

  • Always have a backup.

  • There is no “undo.”

Looking at the Registry

  • Start -> Run -> Regedit

  • Regedit is the only direct access provided by Microsoft.

  • Key Pane, Value Pane

  • Similar to Windows Explorer File View

  • Hierarchical / Tree Structure

  • Root, Tree, Subtree/Branch

Abbreviations for Root Keys






HK => Handle to Key

Registry Statistics (JV16)

Storage of Registry Hives

User info in NTUSER.DAT in Profiles folder

Storage of Registry Hives (cont.)

Win XP


Safe Hacking

  • System / Full Image Backup

  • System Restore Point

    • Regedit

    • Registry, Branch, Key
    • Note any setting before you change it

    • Print Screen or Regedit Export
  • Keep notes / Log of Registry changes

Registry Backup

    • Windows 95

    • Windows 98

      • Automatically creates Registry backup every time Windows starts

      • Can manually create backup with Scanregw.exe from Start – Run (Registry Checker)

Registry Backup

Windows XP

Registration Files (*.reg)

Registry Hive Files (*.*)

Text Files (*.txt)
All Files

Registry Editing Demo

    • Find Desired Key

    • HKLM\Hardware\Descriptions\System\CentralProcessor\0
  • Backup Key

  • Change Name

  • Display New Name

  • Replace Original Name

Registry Tweaks

    • Enhancements – add functionality to Windows

    • e.g., Change the arrow on shortcuts
    • Performance tweaks

    • May increase performance a minuscule amount
  • System security

Increase system security

Registry Tools

    • Regedit

    • Start -> Run -> Regedit
    • Regmon

  • WinDiff and TweakUI

Windows XP SP2 support tools

Registry Cleaning

  • Varied views on value and safety.

  • Always do a prior backup.

  • Removes gunk left by incomplete removal of applications.

  • Compacts unused space resulting from Registry changes.

  • Invalid entries due to data movement, e.g., MRU lists / External drives.

Examples of Registry Cleaning Tools

  • JV16 by Macecraft Software

  • Ccleaner

  • Regseeker

Registry References

  • Regedit Help Screens

  • “Microsoft Windows XP Registry Guide” by Jerry Honeycutt, Microsoft Press

    • “Langa Letter: Testing 10 Windows Registry Cleaning Software Packs”

    • InformationWeek, Oct. 10, 2005
  • -various articles

  • Smart Computing, Feb. 2007 issue and others

Thank You for Coming

  • Questions?

  • Email: