Updated Motherboard BIOS and Lost Windows Activation

That makes sense, as builders don't have the capability to embed the license, hence, there is no way the powershell command will return the key. That powershell command will only read embedded license key, not manually entered license key.

In order to resolve this issue, you need the original license key. When you bought it, did they give you a license key? Or check to see the device itself, is there a sticker somewhere, typically builders would put it on the back. The sticker should have the 25-digit key. This key is absolutely needed to reactivate Windows, and this is not something Microsoft support can look up unfortunately.

You also said this was supposed to be an OEM license? If that's the case, per licensing terms, it cannot be used on another motherboard. If you managed to transfer it in the past with motherboard change, then this may not be an OEM license. Do you still have any purchase record from seller, detailing the type of license you purchased? If you cannot absolutely find the license key, but if you have license purchase proof, you can contact Microsoft support, they might consider a replacement key at discounted rate.

That was probably five to six years ago, if not more. The initial purchase paperwork has long disappeared - and I can find no Windows tag on the outside. (I even went inside.)

I guess here's why I'm at a loss: I've had this motherboard for quite some time. I didn't purchase a separate license, so it was the OEM's initial install. Yet my the machine has always updated with the latest patches. If the motherboard was the issue, why didn't it break when I initially installed it, not after I updated its BIOS?

One possibility is that I believe this was initially a Windows 10 copy, which I upgraded to 11 when 10 was being deprecated. Maybe something strange went on there.

Sort of looks like I need to buy a new copy of Windows.

The challenge here is that we don't know the full context of the license, so we are trying to put pieces together.

What we know so far -

It is 100% NOT an embedded OEM license.

Was it a retail or manually-entered OEM license - we don't know for sure. If you have changed motherboard before and it activated, there's a chance it was actually a retail license, not an OEM license. Your slmgr /dlv shows "retail", but that doesn't mean retail for sure when the partial key is generic key, it can simply mean no license.

It started out as a Windows 10 license you said, so that means your Windows 11 is now, can be on digital license. Are you currently using the same Microsoft account in Windows as the one used to claim the free 11 upgrade?

Try this:

Go to Settings > Accounts > Your info

Click on Sign in with local user instead. follow the steps and finish the rest.

(If you don't see the "sign in with a local account instead option, click on "Stop signing into Microsoft apps automatically" first, then relaunch this page. )

Restart the computer (Do Not skip)

Go to Settings > Accounts > Your info

Click on Sign in with Microsoft account instead. follow the steps and finish the rest

Restart the computer (Do Not skip)

Then go to Settings > System > Activation, run the troubleshooter, choose the hardware change option. When it asks you where it is installed on right now, you should choose the old device name. Then click on Activate button. And on the next screen when it asks you where to transfer it to, choose your new device name. See if that does the trick.

Here's the screenshot. However, after further research - and the fact I really don't use Microsoft products other than the OS on this machine - I'm going to let this ride with the default license.

This screenshot only confirms what we already know so far - 8HVX7 is the generic key. OEM license is not found on board, which is what you already found by using the powershell command. Unfortunately it doesn't give any new information.