[lashkari]

I just went through this with a new Dell XPS for my dad.

I performed a wipe/reinstall (with media created directly from a Microsoft download) and Windows 10 never asked me for a key after reinstalling it, and it reports as being activated.

Seems like they've moved away from requiring an OEM key in addition to the SLIC BIOS signature.

[sfilipov]

They went a step further. Once a Windows 10 machine is activated, a "hash" of its hardware is taken and associated with the product key. When you reinstall Windows 10, the activation service matches your hardware information with the product key. You need to enter a product key only the first time you install Windows 10 on a particular machine.

[Already__Taken]

When I was building machines and asked about the OEM licence, this hardware hash is related to the motherboard. MS consider a new motherboard a new PC, everything else you should get away with changing.