Hi FelixAdam43-
I'm Kevin B. Windows user like you. I do apologize for the inconvenience, let me help you sort things out.
Is there any changes happen before the machine got de activated?
Kindly press Windows key and type: CMD
On the result right click and run it as administrator.
On the command prompt window type: slmgr.vbs /dlv
Hit enter.
On the resulting dialogue, take a screenshot and post it on your next comment.
I await news. Have a blessed day!
Thanks,
Kevin B.
Independent Advisor