Windows 10 Pro expiration/activation problem

Hi, This is my first post to this forum, apologies for the length of this post, but I wanted to try to give as much info as possible.
I have a Windows 10 Pro expiration/activation problem.
I bought a used desktop PC a few months ago, but am now unable to contact the seller to resolve this issue with him. I have tried the usual routes of solving this problem myself, ie; google searches etc; but have drawn a blank to find the correct solution.
Hopefully this forum will be able to lead me in the right direction.
The problem: Approx. every 2 hours I am getting a Windows pop-up message informing me that ''Your Windows License Will Expire Soon... You Need to Activate Windows In Settings''.
When I go to settings it shows ''Windows is activated using your organizations activation service''.
I have used slmgr.vbs /dlv to view the current license, which I think indicates that this PC was possibly once used in a business environment? using KMS.
Also, using the Windows script host, I see the info changes daily, & is now down to 10 days!
I suspect that the seller used either a pirated copy, or a temporary license to install & activate the Windows 10 Pro. There is no Product Key label on the case, it has been scratched off.
The PC is a Dell Optiplex 3010 DF Core i3 3220 @ 3.30GHZ 8GB 500GB. It has an original Microsoft
Windows 7 badge on the case, so obviously it was updated to Windows 10 pro prior to my purchase.
Is there an easy fix for this expiration issue?
Thanks in advance for any help to resolve this.

There should have been a mention of how to contact Microsoft. Failing to get a resolution from them will require you buying a copy of Win10 but might find Win7 cheaper and just redo the computer. The free upgrade to Win10 has been mentioned and still seems to work, do a search on this forum.

Ron64 said:

Windows 7 badge on the case, so obviously it was updated to Windows 10 pro prior to my purchase.
Is there an easy fix for this expiration issue?
Thanks in advance for any help to resolve this.

Yes, your copy of Windows 10 is currently illegal. Even if the KMS activation was a legal activation for the organization that the computer previously belonged to (and I doubt it was), it would be illegal for them to transfer that to you.

Does the Windows 7 "badge" have a product key printed on it, and what version of Windows 7 is it for? Microsoft is still allowing free activation of a matching Windows 10 version with a Windows 7 product key.

You can run showkey plus from this forum and see what product key(s) it produces:
ShowKeyPlus

Reply for Berton: I didn't see a mention of how to contact Microsoft, but if I have to reinstall another Windows OS, I would probably go for the Windows 7 as it's less expensive, then do an upgrade if it's still an offered option.
Thanks.

Reply for navyLCDR: The Windows 7 badge is only a small 1'' sq. badge on the front of the case, but the label where the original product key has been scratched out indicates it was a Windows 7 Pro OA that was installed originally.
I downloaded & ran ShowKeyplus, this is what it showed, though I have ''blanked out'' the actual info for security reasons.

Product Name: Windows 10 Pro

Product ID: xxxxx-xxxxx-xxxxx-xxxxx

Installed Key: xxxxx-xxxxx-xxxxx-xxxxx-xxxxx

OEM Key: Windows 7 OEM marker present in firmware

Hope this info is of more help. What do you recommend is the course of action I should take.
Thanks.

Reply for Superfly: Sorry to show my lack of knowledge, but i only consider myself to be average at best when it comes the programmable workings of PC's.
I don't understand what you mean by or how to change the KMS key in settings. Also you show a 5x5 sequence with the last 5 being 3V66T. I don't want to assume anything...but are you suggesting I add the 3V66T to the 4x5 Product ID that I have, & if so, where do I go to enter this?
Thanks.

Ron64 said:

I don't understand what you mean by or how to change the KMS key in settings.

See this tutorial: Product Key - Change in Windows 10

...you show a 5x5 sequence with the last 5 being 3V66T. I don't want to assume anything...but are you suggesting I add the 3V66T to the 4x5 Product ID that I have, & if so, where do I go to enter this?

Superfly is suggesting your machine may have been upgraded previously and already have a digital licence on Microsoft's activation servers. If that is the case, it should activate automatically if you enter the Windows 10 Pro generic product key:
VK7JG-NPHTM-C97JM-9MPGT-3V66T

Reply for Bree: Tried entering VK7JG-NPHTM-C97JM-9MPGT-3V66T in the change product id in the activation window, got this reply: We couldn't activate Windows. We can't activate Windows on this device because you don't have a valid digital license or product key. if you think you do have a valid license or key, select troubleshoot below.
(0x803f7001) ( followed by the purchasing option).
Thanks.