An improved portable device for start-up of a computer system is disclosed. This portable device for externally starting up a computer system comprises a connection interface to the computer system and a data medium comprising data and executable codes of a host operating system that can be activated by a start-up program of the computer system and configured to automatically detect hardware and/or software elements of the computer system and to activate the corresponding computer drivers. The data medium further comprises data and executable codes of a management software interface, configured to present the computer drivers activated by the host operating system in the form of at least one predetermined generic computer driver, and data and executable codes of a guest operating system that can be activated by the management software interface and configured to manage the hardware and/or software elements on the computer system using the predetermined generic computer driver.