Programmed method and device of portable computer

The invention relates to a method for controlling a portable-computer application program through one key so as to appreciate a required medium and a device thereof. The device is provided with a host, an on-off key on a remote controller, a DVD key and a music key; moreover, if the on-off key is inputted, a normal operating system is controlled to run a system; besides, if the DVD key and the music key are pressed, a specific operating system runs so as to initialize the hardware required by running in a DVD mode and a music mode; and then, modes related to the selected keys are run. Through the control, no complex guidance process is required to be carried out in the invention, but the controlling and running of the required medium can be appreciated by only one key.