product key not found

Question

After troubling shooting the error code says product key not found. I think I threw it away with the box the computer came in as it was included. how do i get a new one or do I even need it because I have 365? I want the pop up to stop that tells me to activate windows. How can I buy a new key?

Answer 1

Hi, I'm John! I will help you with this.

First, just to clarify: Microsoft 365 and Windows activation are separate.

Having a Microsoft 365 subscription does not activate Windows. Windows still needs its own license.

A few questions that may help narrow this down:

1. Did this computer come with Windows already installed when you bought it?
2. Did you recently reinstall Windows or replace hardware (like the motherboard)?
3. Which version are you using now, Windows 10 or Windows 11?

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If the PC originally came with Windows, the product key is often embedded in the motherboard, so you usually don’t need the key from the box. Windows should activate automatically once it connects to the internet.

You can check the activation status here:

• Settings > System > Activation
• If it says “Windows is not activated”, you can also select Troubleshoot on that page and see if Windows can reactivate automatically.
• If the device truly does not have a license anymore, you can purchase a new one from the Microsoft Store directly in the Activation page by clicking “Go to Store.”

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Click "Add comment" to let me know.

Regards,

John J.D.

Answer 2

Windows and Microsoft 365/Office use different licenses. Having Microsoft 365 does not activate Windows, so a valid Windows product key or digital license is still required to remove the “Activate Windows” message.

To resolve this:

1. Check whether the device has a digital license or embedded key
   • If the PC was bought with Windows preinstalled, the product key is often:
     • Preinstalled/embedded in the device firmware (for OEM devices), or
     • On a label/Certificate of Authenticity (COA) on the device or in the original packaging.
   • If it was a refurbished PC, the refurbisher must provide the product key.
   • If Windows was previously activated and tied to a Microsoft account, signing in with that same account may reactivate it automatically once online.
2. If the original key really is lost
   • A Windows installation must have either:
     • A 25‑character product key, or
     • A digital license, to activate.
   • If neither can be recovered (no COA label, no embedded key, no digital license tied to the Microsoft account), a new Windows license must be purchased.
3. How to buy a new Windows 10 license from the device
   • On the PC, go to:
     1. Start → Settings → Update & Security → Activation.
     2. Select Go to Store.
     3. This opens the Microsoft Store app where a Windows 10 digital license can be purchased.
   • After purchase, activation should complete automatically.
4. Office/Microsoft 365 is separate
   • Microsoft 365 or Office product keys and subscriptions do not replace a Windows product key and do not stop Windows activation prompts.

If Windows still cannot be activated after purchasing or recovering a key, use the Activation page’s troubleshooting options or contact the seller if the key appears blocked.

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References:

• Why can't I activate Windows?
• Activate Windows
• Using product keys with Microsoft 365