1. A method for installing in a first computer of a first type a first version of an operating system, including an operating system kernel and a first hardware abstraction layer to interface the operating system kernel to hardware and/or microcode of the first type of computer, and installing in a second computer of a second type a second version of the operating system, including the operating system kernel and a second hardware abstraction layer to interface the operating system kernel to hardware and/or microcode of the second type of computer, the hardware and/or microcode of the first type of computer being different than the hardware and/or microcode of the second type of computer, the method comprising the steps of: loading into a hard drive of the second computer an image of the second version of the operating system, and subsequently, booting up in the second computer the second version of the operating system obtained from the image; loading into a hard drive of the first computer the image of the second version of the operating system; without booting up in the first computer the second version of the operating system obtained from the image, the first computer automatically determining from a configuration file in the first computer which lists the first type of the first computer, that the second hardware abstraction layer obtained from the image is incompatible with the first computer, and in response, the first computer automatically invoking a writing program, stored in a computer readable storage device of the first computer, to automatically replace in the first computer the second hardware abstraction layer obtained from the image with the first hardware abstraction layer to interface the operating system kernel of the image to the hardware and/or microcode of the first computer; and subsequently booting up in the first computer the first version of the operating system, including the operating system kernel obtained from the image and the first hardware abstraction layer which replaced the second hardware abstraction layer from the image.