Computerized method and system computerized method for guiding equipment service personnel while at an equipment work site through a plurality of tasks for troubleshooting the health of a selected system of a selected equipment to determine the nature and extent of service needed for such system. The method allows to provide a database comprising detailed data for health assessment and servicing of a selected equipment and system thereof, and an expert rule-based troubleshooting wizard for eliciting information regarding the selected equipment and system and for providing troubleshooting instructions to determine the nature of the equipment fault and the servicing required for the selected equipment and system. An input/output device at the work site for communicating with the database is provided. The method allows to select the equipment and the system thereof to be serviced and to access the database to interface with the troubleshooting wizard for the selected equipment and system. The method allows to provide in response to a set of prompts to the personnel from the troubleshooting wizard at least one set of observations selected from the group comprising operational performance of the selected equipment, operational performance of the selected system, and fault indications detected in the equipment and system. The method processes the observation information relative to the troubleshooting wizard to determine whether or not said selected equipment and system needs to be serviced, and if so the nature and extent of that service.