On installation Windows is greatly customised to the machine it is installed on, transferring the hard drive to another machine usually gets Windows bootable of sorts but it is luck of the draw and at best will have a lot of problems visible or not.
From the sound of it you may not have "installed" windows onto the hard drive but file-copied it across, that would not make the drive bootable into windows.
Then you also have problem with the Windows authentication (licence) which is against the physical hardware of the computer.