Windows 10: Free upgrade to Windows 10 LOST ITS ACTIVATION SOMEHOW

I have a Windows tablet that CAME with Windows 8.1, including me calling Microsoft to activate Windows the usual way one time after I factory reset it when it had Windows 8.1. I received the "free upgrade" to Windows 10 some months ago and now I see a message in the corner "Activate windows. Go to settings to activate windows." How do I fix this? I googled the problem but NOTHING came up

:)

 

Windows 10 Language Pack fails to install

Same with Russian display language on Win 10 Pro (upgraded from 7 Pro) x64. I was able to successfully install it on this same machine but Win10 somehow lost its activation so I reinstalled 7, applied all updates and upgraded to 10.

 

Get Windows 7 product key from imagebackup to activate Windows 10

I upgraded my computer to Windows 10 over 1 year ago through the insider builds. Somehow when the RTM of Windows 10 came out, I lost the activation that I had from Windows 7 that I was running on the system originally. I've been running Windows 10, unactivated
since then. I want to make sure that I can activate it before the free upgrade goes away. I have a WindowsImageBackup on my external drive that I made before I did the original upgrade (which activated at the time). Since I need a Windows 7 product key to
activate Windows 10 for free, how do I get the product key off of the WindowsImageBackup? Can I query it somehow? Can I install that backup to a virtual machine (I've never worked with a virtual machine. I've read some posts that suggested that might be the
way to do this.)?

 

Run showkeyplus from this forum, click on the product keys to blank them out and post the results here.
Showkey - Windows 10 Forums

Then right click on the start icon, select Command Prompt (Admin). Run slmgr /dlv

Post that result here. We can help troubleshoot the activation problem with that information. Your results should look like:

 

You should not have had to call Microsoft to activate it (Windows 8.1) after doing a factory Reset? The Windows 8.1 key will be embedded in the BIOS. It should have activated with that key automatically?
Also have a look in Settings > Update & Security > Activation > to see what it says there.