I bought a chromebox off amazon last year for cheap, i7 cpu for around $130. I went through and updated the BIOS so I could install Win 10 over it which I did. It somehow self activated without a need for a key. I have a full version of Win 10 Pro on it. It's not linked to my microsoft account either. So I have no clue how it did it since it's originally a chromebox.
it had 2 GB ram and 16 GB m.2. I removed those and installed a 256 GB m.2 and 16 GB ram. Use it for my camera security system.