If the unit shipped with Windows 8 and you bought it from a major OEM like Dell or Asus, check the activation status. If the OS is able to acivate, your copy is legit. OEM machines do not have product keys on the COA sticker anymore, as they are encoded in the BIOS. You can use a key finder app to get the key, but it won't do you any good on any other machine, or with a retail copy of Windows 8.