dilettante
MIS
I may find myself starting all over again before time runs out, but here is what I have done so far and it seems to work fine.
If you paid for a Windows 8 upgrade back in 2012-2013 ($39.95 + $14.99 for optional DVD install media) you have a Product Key.
I'd never used it but held onto it.
I went to another machine with WHS 2011 on it (you need a Windows 7 or later machine) where I could run the Media Creation Tool to download Windows 10 Setup to a USB flash drive.
Then back to the Vista machine, I was able to boot to the USB flash drive, clean-install Windows 10 using the Windows 8 Upgrade Product Key... and it went fine. it even shows as "Activated" so I expect no further grief.
If you paid for a Windows 8 upgrade back in 2012-2013 ($39.95 + $14.99 for optional DVD install media) you have a Product Key.
I'd never used it but held onto it.
I went to another machine with WHS 2011 on it (you need a Windows 7 or later machine) where I could run the Media Creation Tool to download Windows 10 Setup to a USB flash drive.
Then back to the Vista machine, I was able to boot to the USB flash drive, clean-install Windows 10 using the Windows 8 Upgrade Product Key... and it went fine. it even shows as "Activated" so I expect no further grief.