We have several machines at work that came with 7 Pro keys that we'll never use. I've tried to use one on another PC and it won't activate for some reason. Is it possible that they'll only work on these laptops they were supplied with? Seems odd and I've never heard of this before..
Some keys are OEM, Original Equip Mfg. They are good only for the machine it is associated with. Does the key have the letters OEM, included with the number configuration?
OEM keys are cheaper than most. They are usually used when you buy a computer from Dell, etc. The OS is already preinstalled. You cannot use that OS on any other machine.