A liquid crystal display (LCD) and a method of driving the same are disclosed. The liquid crystal display includes a liquid crystal display panel; a backlight unit; a panel drive circuit; a timing controller; an internal memory; a self-screen drive controller; a scaler unit; a selection unit; an internal power circuit; an external power circuit; and a microprocessor that blocks an output of the external power circuit from being supplied to the scaler unit in a self-screen drive.