This message appears how do I fix. I have an online subscription and want to know if there is a product key.

The message in the screenshot is from Windows activation and means Windows cannot find a valid Windows product key on the device. A Microsoft 365 online subscription does not provide a Windows product key, so it cannot be used to activate Windows.

To resolve this:

1. If the PC originally came with Windows preinstalled (OEM):
   • The key is usually embedded in the device firmware and Windows should activate automatically once the correct edition is installed and the device is online.
   • If activation still fails, use the Troubleshoot button shown in the screenshot and follow the on‑screen steps.
2. If Windows was previously activated with a digital license linked to a Microsoft account:
   • Sign in to Windows with the same Microsoft account that was used before. Windows may reactivate automatically using the digital license.
3. If Windows was activated using a retail key:
   • Enter that key via Change product key in the same activation page.
   • If the key cannot be found, it is not stored as a simple file on disk; it must be retrieved from purchase records, email receipts, or the original packaging.
4. If none of the above apply (for example, this is a new build or the original license is lost):
   • A new, genuine Windows license must be purchased and its product key entered via Change product key or by buying directly through Get a new licence in the Microsoft Store app.

A Microsoft 365 subscription only covers Office apps and services; it does not activate Windows and does not come with a Windows product key.

References:

• I cannot find my product key even though I purchased Windows - Microsoft Q&A