After hardware change, can't activate Windows.

Since this is a retail license, you can contact Microsoft support to get this sorted:

https://support.microsoft.com/en-us/topic/customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2

Hope this helps!

Hello, Bill Purosky.

Quote: "Note, I orginally bought this as Windows 8.1, and upgraded to 10. I've also changed the computer at least twice."

Unfortunately, the Windows 10 license obtained as part of the free upgrade promotion from genuine 7/8/8.1 in 2015-16 is permanently assigned to the PC that participated in the promotion and cannot be transferred. These were the terms of the action. Replacing the motherboard is a new device and the license has become invalid. Previously, there was a bug that allows you to activate such an OS, but Microsoft blocked this feature.: https://devicepartner.microsoft.com/en-us/communications/comm-windows-ends-installation-path-for-free-windows-7-8-upgrade

In this case, you will need to purchase a separate license for the standalone (BOX or ESD) version of Windows 10/11, perform a clean install and activate it with a unique key from the purchase package.

The hardware change (motherboard/CPU) has broken the link between the existing digital license and the current device. The Activation troubleshooter is failing and the system is now in “Notification” state, even though the edition is Windows 10 Pro Retail.

From the provided context, there are only two supported ways forward when activation after a hardware change fails and the troubleshooter cannot repair it:

1. Try reactivating with a product key (if available)
   • Go to Start > Settings > Update & Security > Activation.
   • Select Change product key.
   • Enter the Windows product key that was used on this PC before the hardware change (for example, the key from the original retail media, if it is still valid).
   • Complete activation.
   This path is explicitly documented for error 0x803F7001 and other “no matching license found” cases after a hardware change.
2. Use the exception path or contact Microsoft support
   • A Windows license is tied to device hardware; replacing the motherboard is considered a significant change and can prevent Windows from finding a matching license.
   • Microsoft provides an exception path for transferring a Windows license after a hardware change, but it depends on the Activation troubleshooter being able to complete and offer the “reactivate after a hardware change” link. In this scenario, the troubleshooter is not succeeding, so the exception path cannot be used from the device UI.
   • When the troubleshooter cannot reactivate and the device shows a Retail channel license that previously activated, the remaining supported option is to contact Microsoft support so that an agent can locate the digital license on the Microsoft account and manually reactivate it on the new hardware. This is the resolution used in similar cases in the provided context.

If the original Windows was preinstalled (OEM) on an earlier machine, or if the upgrade path (for example, free upgrade from Windows 8.1) is no longer eligible for transfer, support may determine that a new license purchase is required. In that case, use Start > Settings > Update & Security > Activation > Go to Microsoft Store to purchase and activate a new Windows 10 license.

References:

• Fix Windows 10 activation error 0x803F7001
• Get help with Windows activation errors
• Using the Windows Activation troubleshooter
• Unable to activate windows after hardware update - Microsoft Q&A
• Windows reactivation fails - Microsoft Q&A
• Reactivate Windows 11 - Microsoft Q&A
• Unable to use troubleshooter for windows activation - Microsoft Q&A