Activation notice

I have Windows 10 Pro installed. I just received notification that I have to activate it. It states Windows is activated using your organization's activation service. I don't have an organization activation service. If I wanted to do a fresh install of Windows, can I use the files on my other hard drives? Would they be compatible with the new Windows install? And how would I do the install? I really at a loss here. I fly online and have a lot of files connected to X plane. I hope someone can make sense of one saying. And of course Microsoft is no help. They just give you a virtual agent. I have copies of Windows 10 home, Pro, Education and Enterprise. All with KMS.Thanks

I think my best bet would be to buy new Windows 10 home edition and install it. Maybe we could talk about the ramifications of this.My Windows is stored on Disk C. Would I format that drive?? If I saved the programs that are currently on disk C can I use them after the new installation?

I purchased Win 10 home. All is good. Thanks

just had the same issue with the lenovo i bought from a garage sale, had to replace most of its guts and then shortly after reinstalling windows 10 i got that message. glad i had a windows 7 pro disk i never used. just entered the key from that and it activated it and now no more annoying pop up message. dont have a clue to where the windows 10 pro usb drive came from that came with the laptop though, but as long as it works thats all that matters.