1. A method of intelligent monitoring and maintenance of a system by means of a plurality of software tools operating on a separate computer processor having a memory and an output device for interaction with an operator, the system comprised of functional components having an online built-in-test functions, said method comprising: providing an archived system database residing in the memory of the separate computer processor, the archived system database containing prior data associated with expected and previous results of built-in-tests; accessing test data relating to functional components of said system; extracting parameter information for said functional components of said system, said step of extracting parameter information including monitoring the results of the built-in-tests; determining the presence of non-ambiguous faults and ambiguous faults based upon test data associated with the results of the built-in-tests; providing an indication on the output device to the operator to replace said functional components associated with non-ambiguous faults as determined by the results of the built-in-tests; while an ambiguous fault has not been examined, then performing the following steps: selecting an ambiguous fault for examination; extracting ambiguous data from test data associated with the results of built-in-tests from which an ambiguous fault is determined; reducing ambiguity in said ambiguous data; performing inferential processing and trend recognition of said ambiguous data using prior data, and simulating performance of said system using models of said system and previous said prior data about said system; and identifying new data present in said extracted parameter information; updating the archived system database with the new data wherein the new data becomes prior data.