According to one embodiment, an EC/KBC reads data of an acceleration sensor. The EC/KBC determines whether a computer is in a top heat state. If the EC/KBC determines that the computer is in the top heat state, it notifies a BIOS stored in a BIOS-ROM of a message to this effect. The BIOS which is notified from the EC/KBC that the computer is in the top heat state notifies an OS (Operating System) of the message to this effect. The OS sets a CPU to a power saving mode by an existing means such as the power saving utility of the OS, and sets the computer to the power saving mode.