1. A portable start-up device for connection to and starting up of a computer system, the portable start-up device comprising: A) a connection interface for connecting the portable start-up device to the computer system; B) a storage medium internal to the portable start-up device, the storage medium containing: 1) first storage space which contains data and executable code of an underlying host operating system that can be initially activated by a start-up program of the computer system; and, the underlying host operating system being capable and configured to provide automatic detection of one or more hardware elements of the computer system and for activating driver programs specified for use with the detected hardware elements; 2) second storage space for storing of data and executable code of a guest operating system which a user of the portable start-up device may desire to utilize for booting of the computer system; 3) third storage space which contains data and executable code of a management software interface, the management software interface being operative to: a) present the driver programs activated by the underlying host operating system in the form of one or more predetermined generic driver programs; and, b) activate the guest operating system, in a manner so as to make available for use by the guest operating system one or more of the predetermined generic driver programs.