The present invention relates to a computer system having a CPU, a power management processor, a switch, an external signal reception means such as a modem, a timer, and a power supply in circuit communication. Optionally the system may also include an override circuit and a glitch circuit. The power supply has several power supply states, which are controlled by the power management processor responsive to the CPU, the switch, the modem, the timer, the glitch circuit, the override circuit, and the power management processor itself.