It’s possible, but a little tricky. You need to extract the product key from the Windows registry hive files from the target drive.
There’s different ways to do it, but probably the quickest and easiest way is with Nirsoft’s ProduKey:
- Download, extract, and run the program (it will show your own key by default)
- Press F9 to bring up the Select Source dialog
- Select Load the product keys from external Software Registry hive
- Browse to the
SOFTWARE registry hive. For example, if you have the drive from the other system mounted as drive
Z:, then you would probably select
It should read the hive file from the other copy of Windows and display the appropriate product key.
In this screenshot, I ran ProduKey in Windows XP (installed in
C:) and then extracted the key from Windows 7 (mounted as
T:). Note how it still says
C:\Windows since Windows 7 was indeed installed in
C:, even though it’s files are currently accessible from