Abstract: An apparatus and a method for preventing a personal computer from being illegally used are provided. A personal computer includes a RAM for storing a plurality of programs having application programs and an operation system, a flash memory of a BIOS ROM for storing a BIOS including a POST module for checking the state of a computer and booting the computer when power is applied and an interrupt processing module for managing peripheral equipments, a microprocessor for executing the plurality of programs and the BIOS, and a CMOS RAM for storing system information which must be maintained though power is intercepted. Both the CMOS RAM and the flash memory of the BIOS ROM respectively include areas for storing passwords. If A password input by a user is identical to a first password stored in CMOS RAM, booting the computer is processed when the first password is set in the CMOS RAM.

Abstract: A portable computer has a radio function implemented by a radio set included therein. The portable computer also has a switch for selecting main power for the entire system or a radio power for the a radio set, a micro-controller for outputting a power supply selecting signal and a sound source selecting signal according to the operational state of the switch unit, a power branching unit for branching and outputting power into main power to operate the portable computer or into radio power to play the radio set according to the power supply selecting signal outputted from the micro-controller, and a sound source selecting unit for selecting and outputting a signal from the radio set or a signal from the portable computer according to the sound source selecting signal received from the micro-controller.

Abstract: A control apparatus for turning off a computer system is provided which protects a display from damage. Also, methods for turning off a computer system are provided which protect a display from damage. The control apparatus and methods for turning off power supplied to a computer system having a display provide that power supplied to the display is turned off first and power supplied to the entire computer system is turned off last. A first control unit outputs a first signal to initiate cut off of power supplied to the display if a power switch is turned off and also outputs a second signal to cut off power supplied to the entire computer system after power to the display has been cut off. A second control unit receives the first signal and outputs a third signal to cut off power supplied to the display in response to the first signal.