Windows 10: Activating Win10Pro from a graveyard VistaPro-->Win7Pro pc. Details provided

I know activation issues can look suspect so I'll detail what I can. In-laws letting me clear out their old business pc's. Win win. This old hp compaq dx2400 with core2duo will work well for someone who can't affort better but isn't worth spending on. I have the original Vista Pro product key sticker. But this PC was running Win7Pro when I got to it. No product sticker anywhere. It was probably remotely upgraded at some point. This pc has been out of service and no one knew the password so I couldn't log into to the 7Pro OS in order to get the key. I did a DBAN to erase all their business data

:)

 

How to activate win10pro on new computer using win7pro license?

My computer died. I got a new motherboard and cpu, downloaded and installed win10pro. When I tried to activate using my win7pro upgrade product key, it didn't activate. Tried logging into my Microsoft account, that didn't work either. How can I get
this activated?

 

Win10Pro transfer to new PC

I bought a PC with Win7Pro already installed (the sticker refers to OEM). This was updated to Win10Pro. The motherboard on this PC has now died and I need to purchase another. Most come with Win10Home and I would wish to transfer the licence from the dead
PC to the new one. Unfortunately, I do not have a Win10Pro licence key to hand (or access to it as the PC is dead). I do have the original disc and the key for the Win7Pro. I cannot find a straightforward answer as to whether I can upgrade a Win10Home installation
to Win10Pro using the Win7Pro key. Please advise.

 

Networking Win10Pro to Win7Pro stopped working. How do I fix it?

Thank you, Pauli O, for your reply, instructions and the link.

I was never able to get the two computers talking to each other using a "Private" network, so I've been using "Public" all this time. (The Modem/Router is secure, with a strong password.) I do not have Powershell installed. I do have both computers with
the same login username and password.

I do not get the error "\\PCNAME path not found" The error I do get is "Your computer appears to be correctly configured, but the device or resource (PCNAME) is not responding."

All the services you listed are running and set to Automatic. Network Discovery and File and Printer Sharing are set to On and Password protected sharing is Off.

Both computers "see" the other in the Network folder. The Win7Pro computer can access, read and write files and folders on the Win10Pro machine. The Win10Pro computer cannot access the Win7Pro machine.