First of all, I do not support any kind of software piracy. This question does refer to piracy but from a technical perspective so I hope this is on topic here. While reviewing laptops on Amazon shopping site, I came across a couple of models I think from Acer that were offering DOS or Linux as OS. The description came with an interesting disclaimer. Manufacturer recommends usage of only genuine Windows 10 with this machine. Pirated version of Windows cannot be installed on this laptop Now how would a laptop know that windows being installed is pirated in any way? I think you can always install Windows 10 without a key and just use it forever with its limitations like no ability to personalize or watermarks and other such limitations, technically you are using it without paying for it. Would the Firmware be having some intelligent built in mechanism to talk to MS activation servers when online and check if the windows copy is genuine or not, and if not somehow block the usage it first place, just a thought?