Recover Windows 7 / Vista / XP Product Key from ntuser.dat in Corrupted or Unbootable System

Product key, or used to more commonly known as CD key or serial number for Windows XP, Windows Vista and Windows 7 is as good as the license to use the operating system. Although you may have the paper license for the OS, however due to introduction of Windows Genuine Advantage (WGA) anti piracy feature, if Windows XP or Windows Vista and Windows 7 is installed with invalid or wrong product key, the users will be subjected to much annoyance. Thus if you don’t record down the product key, the product key may be lost once you reformat or reinstall Windows, or the computer corrupts and unbootable.

There are plenty of ways and tools to retrieve product key from Windows, as long as you can still manage to boot and log on to Windows. If Windows corrupted, hard disk corrupted, system no longer functional or computer no longer able to boot up, the tricks will not be able to work. In the case where you need to recover a lost product key from an inaccessible Windows environment, utility by Dagon Design may be useful.

Instructions

The first step is getting the ntuser.dat file from the computer. In most cases the easiest method is to remove the hard drive, and connect it to a working machine.

ntuser.dat is generally located here:

C:\Documents and Settings\(User Name)\ntuser.dat

Where (User Name) is the primary account – Most often it is ‘Owner’ or ‘User’ or simply your name.

Now that you have the file, you need to be able to view it. Download loadhive.exe from MatCode.

Just run the program and select the file. It will show you a message with more information.

IMPORTANT: Do not close this program until you are finished viewing the registry, as it temporarily loads the file, and unloads it again when you exit.

Now run Registry Editor (regedit). Under HKEY_LOCAL_MACHINE you will notice a new sub-key called NTUSER. Starting with NTUSER go to Software > Microsoft > Windows NT > Current Version.

In the right window, double-click on DigitalProductID. This is the entry that contains the encoded product key.

We want the information in bytes 52 to 66. You can use the chart below for reference. We need the 15 sets of numbers where the 1’s are located.

0000  00 00 00 00 00 00 00 00  ..
0008  00 00 00 00 00 00 00 00  ..
0010  00 00 00 00 00 00 00 00  ..
0018  00 00 00 00 00 00 00 00  ..
0020  00 00 00 00 00 00 00 00  ..
0028  00 00 00 00 00 00 00 00  ..
0030  00 00 00 00 11 11 11 11  ..
0038  11 11 11 11 11 11 11 11  ..
0040  11 11 11 00 00 00 00 00  ..
0048  00 00 00 00 00 00 00 00  ..
0050  00 00 00 00 00 00 00 00  ..

Now that you have the 15 byte encrypted code, type it into the web-based decrypter tool: Windows XP Key Decrypter Tool

Just click ‘Decrypt Code‘ and you will have your 25 digit Windows XP product key!

Troubleshooting

If you cannot find the DigitalProductId key in the file you loaded earlier, try the software hive located here:

\%SystemRoot%\System32\config\software

Load it the same way as before. Under regedit, it will generally create the new entries here:

HKEY_LOCAL_MACHINE\SOFTWARE_00 (although the loadhive program will tell you where it puts it).

Source: Dagon Design