Our teacher gave us 2 used computers and asked us to format them and we did. Then we installed Windows 10 on both. Now he comes and says "I don't want any OS on them". Of course, when a computer is just manufactured, it has no OS. He wants us to revert the computer to that state, to disassemble and reassemble its parts, and install any OS on it. But it seems to me that the first thing any OS is programmed to do is not allow the user to delete it when there are no installed operating systems on the computer. It seems the needed result can't be achieved. Or is it? I don't know. Since we will disassemble it anyway, I might learn how to reset everything using the hardware. So can you do that in any way (even using hardware; maybe unplug or change some cables)?
Regardless of the context is, I have Win 10 on 2 computers each, and I want to remove it and revert the computer to the "dead box" state