Windows 10: Reinstall windows 10 - product key needed?

I have a Windows 10 PC that suddenly stopped working. Recovery is not working. Rollback is working forever without any progress. Reset PC from the recovery menu does not work. So I guess I have to reinstall windows with the media creation tool. But I don't know my windows product key. Will I need to enter it when I reinstall Windows on the same hardware? If yes, how can I find it?Thanks,Thomas

:)

 

Reinstall Windows 10 with OEM product key

When you upgraded from a previous version of Windows or receive a new computer preinstalled with Windows 10, what happened is the hardware (your PC) will get a digital entitlement, where a unique signature of the computer will be stored on Microsoft
Activation Servers. The Windows 7 or Windows 8 genuine license you were previously running will be exchanged for a diagnostics key.

Anytime you need to reinstall Windows 10 on that machine, just proceed to reinstall Windows 10. It will automatically reactivate.
You will prompted to enter a product key a couple times through the installation, click I don't have a key and Do this later.

There is no need to know or get a new key, but if you have issues with Digital Licensing or the Activation Troubleshooter, you can utilize an existing Windows 7 or Windows 8/8.1 product key
you already ownto reactivate if necessary. or use the reset function in Windows 10.

Step 1: How
to download official Windows 10 ISO files

Step 2:

• How to: Perform a clean install of Windows 10

 

How to reinstall Windows 10 if my computers used the free upgrade from 7 and 8?

Will windows 10 still accept the license keys from 7 and 8 now if I reinstall my computer?

Does Microsoft keep a list of users who upgraded to Win 10 using their 7 and 8 keys so that when users need to reinstall windows 10 the old keys would work?

Do I need to call in Microsoft to ask them to activate my Windows 10 when I give them my win 7 keys?

Both computers are laptops. The windows 7 machine had the serial printed on the back, and I needed to enter that when I upgraded to 10. The windows 8 machine had the serial built in inside its boot system so I didn't need to enter the key when I upgraded to 10, but I did manage to write down the keys using a fetcher program.

 

Windows 10 Product Key

Hi Oscar,

Since the laptop has no battery compartment wherein the product key is usually located, we recommend that you follow these steps to find your Windows product key:

• Press Windows + X and select Command Prompt (Admin).
• Enter this command: wmic path SoftwareLicensingService get OA3xOriginalProductKey
  and hit Enter.

Also, if you're looking to reinstall Windows 10 after a hardware replacement, we recommend that you follow the steps provided in this

article.

Let us know if performing these steps resolved the issue.