Where to find product key on laptop emachines E627?

A computer itself does not require a product key they have service codes and for desktops they are located on the back, top or behind the front door panel if it has one product keys for a computer is usally for OS or operating systems and those can sometimes be found for Windows based computers on a green or silver tag stuck to the same as the service codes. In any other case it is with the OS disk or book that came with the computer or that was bought can consist of 16-24 letters and or numbers