msg says Product Code Not Valid

Question

I recently had a problem with an HP Omni Pro 110 All in One so I removed the Hard Drive and Installed it into this HP Compaq Pro 4300 All in One and I keep getting a notice to enter My product Code and it isn't excepted...?!?

Answer 1

I Change the Product Code that is incomplete in the update window to the One from My Windows Installment Package Disc and Microsoft Supplied Product Code...

Answer 2

I even tried the Code of the Compac 4300 and it is Not excepted...

Answer 3

The message appears because the Windows product key on the hard drive does not match the license that is valid for the HP Compaq Pro 4300 hardware.

When Windows is moved to different hardware (especially OEM systems like HP all‑in‑ones), activation often fails because:

• The original license was tied to the old PC’s motherboard/firmware.
• The product key stored in firmware on the new PC does not match the edition or media of Windows on the moved drive.

To resolve this:

1. Use a product key that matches the Windows edition installed on the drive and is valid for this PC:
   • Go to Start > Settings > System (or Update & Security) > Activation and select Change product key.
   • Enter a valid Windows product key that corresponds to the edition installed (for example, Windows 7 Pro vs Home, or Windows 10 Home vs Pro).
2. If the key still shows as not valid:
   • The key may be blocked or otherwise invalid. In that case, a new genuine Windows license must be purchased and activated on this PC.
3. If the HP Compaq Pro 4300 came with Windows preinstalled and its own embedded OEM key in firmware:
   • The license is tied to that machine’s original edition. If the edition on the moved drive does not match, activation will fail with a “product key not valid” or “key not compatible with this edition” type of error. Installing the correct Windows edition for the embedded key and then activating is required.

If the product key has been used on more PCs than allowed (for example, reused from another pre‑owned PC), it will not activate and a new product key or copy of Windows is required.

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References:

• Windows installation fails with error: The product key entered does not match any of the Windows images available for installation. Enter a different product key
• Why can't I activate Windows?
• Get help with Windows activation errors
• I cannot find my product key even though I purchased Windows - Microsoft Q&A
• Unable to activate windows after hardware update - Microsoft Q&A
• Can't Activate Windows after MSFT Forced Upgrade to 11 - Microsoft Q&A
• Unable to use troubleshooter for windows activation - Microsoft Q&A
• Retrieve Product Key / New Windows 11 install - Microsoft Q&A