Note: it is a legal company machine. Unfortunately, my co-worker responsible for the keys isn't reachable any more. But I (representing my employer) am legal user of the keys in that currently non-bootable Windows 10 installation.

  1. I have a damaged, non-booting, but activated Windows 10.
  2. I have also a booting, working, but not activated Windows 10.
  3. I want to activate (2) with the license key of (1).

How can I get the license key from (1)? Important: I can't boot this install, but I have full access to its hard disk (as the administrator of (2) ).

Note 2: After the key is found, (1) will be deleted.

Result: Finally I reinstalled the Win10 with the OEM Win7 license key on the bottom of the laptop.

  • What caused the windows to not boot? Is the MBR damaged or any other possible known source?
    – Jesse
    Jan 25, 2017 at 10:03
  • This might get you going: howtogeek.com/206329/…
    – Alex
    Jan 25, 2017 at 10:09
  • @Alex Thanks! Also your link is very useful for the case if ProduKey in the accepted answer wouldn't work.
    – peterh
    Jan 25, 2017 at 12:25
  • 1
    Shouldn't windows 10 have a digital entitlement and just activate magically?
    – Journeyman Geek
    Jan 25, 2017 at 15:27
  • @JourneymanGeek Probably not. But the OEM Win7 license key on the bottom of my laptop finally worked, unfortunately only with a clean reinstall.
    – peterh
    Jan 25, 2017 at 15:27

2 Answers 2


If the hard disk of the non-working computer is attached to another machine, you can download ProduKey , and point it to the other hard drive to retrieve the Key. This will work in most standard cases unless the computer was bought with an OEM provided Windows installation, in which case the key is not reusable anyway, as @djsmiley2k pointed out (Thanks!)

  • 1
    If the key is OEM, you might not be able to reuse it anyway - worth adding to the answer I feel. Jan 25, 2017 at 10:56
  • @djsmiley2k Thanks. It is a legal limit or a technical one?
    – peterh
    Jan 25, 2017 at 12:23
  • @peterh According to howtogeek.com/261053/… , it's not allowed, OEM licenses are tied to hardware since they are sold to manufacturers at discounted prices. Jan 25, 2017 at 12:35

I'd recommend Superfly Inc.'s ShowKeyPlus instead. It not only correctly identifies OEM keys (you'll need to run it from a bootable USB running Windows 8.1 or 10 on machine #1), but it is also free.

Screencap: ShowKeyPlus providing info about OEM keys

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