In this research we adopted a statistical model as a measure to control the login procedure. This model considers the login procedure as a test of statistical hypothesis and hence presents a more reliable" way to allow authorized user to access, to the system and of course denies unauthorized users (hackers) accessing the system. This computerized model takes a password as a hypotheses subject to test. The system then calculate the " Test Statistic Value (TSV)" upon which the system will judge wether it is the correct or incorrect password. The calculation of the (TSV) depends on the number of tries and on the variations between the tested password and the correct one. The research work include also includes metricated measures to protect the HD , as intended initially in the proposal of this research idea . Intensive knowledge of the MS-DOS groups of the programs, (where some of which had to be dealt with), is required. This by itself was a big task due to the design of MS-DOS itself. A number of testing and evaluation procedures to measure the robustness of the system were also applied to metricate the system, and proved successful. A number of proposed ideas also presented for future developments in this line of research and development.