How To Recover Windows Product Key (Serial Number) From Registry, Even If PC is Unbootable

Your installation of Windows no longer boots, and unfortunately you don't have a copy of your Windows product key in order to reinstall the operating system? Don't worry, it's possible to recover Windows Product Key from registry in offline mode, even if Windows is no longer bootable.

This article explains how to find and recover Windows Product Key from the registry, extract Windows Serial Number from registry in offline mode, and get Windows CD Key from unbootable computer.

Contents

1. Intended audience of this article

This article is for people who want to reinstall Windows, but lost or forgotten Windows Product Key.

Using Registry of your old Windows installation, you can retrieve Product Key once upon a time used to install Windows. This method works even if Windows is broken and unbootable, or if your computer crashes during startup.

All you need to recover your Windows Product Key is readable (non-broken) HKEY_LOCAL_MACHINE\SOFTWARE Registry hive.

2. Solution in a nutshell

  1. Boot into EBCD
  2. Run EBCD Registry Editor, choose Windows installation and open HKEY_LOCAL_MACHINE\SOFTWARE Registry hive
  3. Export HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion registry key to text file on USB thumbdrive.
  4. Boot into Windows, open registry key dump in Notepad, copy DigitalProductId value into the clipboard.
  5. Paste clipboard into Javascript form on this website to decode your Product Key.

3. Extracting DigitalProductId from registry

1) Download EBCD and burn it to CD/DVD according to the instructions, then set up your BIOS to boot from CD. Demo version of EBCD will suffice for the purpose of this article.

2) Boot EBCD and run Registry Editor from the main menu:

Recover Windows Product Key With EBCD - Main Menu
Recover Windows Product Key With EBCD - Main Menu

3) Wait for EBCD Registry Editor to start:

Recover Windows Product Key With EBCD - Waiting for Registry Editor to Start
Recover Windows Product Key With EBCD - Waiting for Registry Editor to Start

4) Choose Windows Installation to extract Product Key (this screen will not appear if you have one copy of Windows installed on your PC):

Recover Windows Product Key With EBCD - Choose Windows Installation to Extract Product Key
Recover Windows Product Key With EBCD - Choose Windows Installation to Extract Product Key

5) Choose HKEY_LOCAL_MACHINE\SOFTWARE on this screen:

Recover Windows Product Key With EBCD - Choosing Registry Hive containing Windows Product Key
Recover Windows Product Key With EBCD - Choosing Registry Hive containing Windows Product Key

6) EBCD Registry Editor is loading Registry Hive with Windows Product Key:

Recover Windows Product Key With EBCD - Registry Editor is Loading Registry Hive
Recover Windows Product Key With EBCD - Registry Editor is Loading Registry Hive

7) Using arrow UP and DOWN keys on keyboard, go to Microsoft key and press ENTER:

Recover Windows Product Key With EBCD - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft key
Recover Windows Product Key With EBCD - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft key

8) Using arrow UP and DOWN keys on keyboard (and optionally PAGE UP and PAGE DOWN), go to Windows NT subkey and press ENTER:

Recover Windows Product Key With EBCD - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT subkey
Recover Windows Product Key With EBCD - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT subkey

9) Using arrow UP and DOWN keys on keyboard, go to CurrentVersion subkey and press ENTER:

Recover Windows Product Key With EBCD - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion subkey
Recover Windows Product Key With EBCD - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion subkey

10) Press TAB to switch input focus to the right panel. Scroll down with arrow keys and PAGE DOWN / PAGE UP keys:

Recover Windows Product Key With EBCD - Switching to Value Edit Mode in Registry Editor
Recover Windows Product Key With EBCD - Switching to Value Edit Mode in Registry Editor

11) Make sure DigitalProductId value of type REG_BINARY exists:

Recover Windows Product Key With EBCD - Looking For DigitalProductId Value
Recover Windows Product Key With EBCD - Looking For DigitalProductId Value

12) Press F3 on the keyboard to open Registry Key Export dialog window, then click [...] button with a mouse:

Recover Windows Product Key With EBCD - Registry Key Export Dialog
Recover Windows Product Key With EBCD - Registry Key Export Dialog

13) In this Save File common dialog, click on some writeable device (like USB thumbdrive), then click on the text area next to "File Name:" label and type some file name from keyboard. File name must have .txt suffix.

Recover Windows Product Key With EBCD - Saving Dump of Registry Key
Recover Windows Product Key With EBCD - Saving Dump of Registry Key

14) Click OK to confirm export of Registry Key to the file:

Recover Windows Product Key With EBCD - Confirm Export of Registry Key
Recover Windows Product Key With EBCD - Confirm Export of Registry Key

15) Message like this should appear on the screen:

Recover Windows Product Key With EBCD - Registry Key Has Been Exported Successfully
Recover Windows Product Key With EBCD - Registry Key Has Been Exported Successfully

16) Choose "Reboot" in the EBCD Main Menu:

Recover Windows Product Key With EBCD - Reboot
Recover Windows Product Key With EBCD - Reboot


Eject EBCD from CD drive and boot into Windows (maybe on the different PC, where you are browsing this page). Plug USB thumbdrive with registry key dump and open My Computer:

Recover Windows Product Key With EBCD - Open My Computer
Recover Windows Product Key With EBCD - Open My Computer

Open USB thumbdrive with registry key dump in Exporer:

Recover Windows Product Key With EBCD - Open USB Thumbdrive in Exporer
Recover Windows Product Key With EBCD - Open USB Thumbdrive in Exporer

Double-click on registry key dump file to open it in the Notepad (won't open if it wasn't saved with .txt extension):

Recover Windows Product Key With EBCD - Open Registry Key Dump in the Notepad
Recover Windows Product Key With EBCD - Open Registry Key Dump in the Notepad

Find "DigitalProductId"=... registry value, select it using your mouse or SHIFT + arrow keys and the copy it to the clipboard:

Recover Windows Product Key With EBCD - Copy DigitalProductId Value to the Clipboard
Recover Windows Product Key With EBCD - Copy DigitalProductId Value to the Clipboard

4. Decoding DigitalProductId

Paste "DigitalProductId"=... into this form:

5. References

  1. Inside Windows Product Activation, a paper from Fully Licensed GmbH:
    http://www.licenturion.com/xp/fully-licensed-wpa.txt
  2. Getting Windows Product Key from Registry, an answer from SuperUser.com:
    http://superuser.com/questions/617886/recovery-disk-install-to-a-specific-partition
  3. Interactive JavaScript-based Microsoft Digital Product ID Decoder, by Ed Scherer:
    http://www.ed.scherer.name/Tools/MicrosoftDigitalProductIDDecoder.html