provided is a method of variably establishing storage areas of a flash memory according to the status of a system in a computer having flash memory in which booting data and execution data are stored . the computer includes : a flash memory including a storage area that is divided into a boot area for storing booting data and a cache area for storing execution data , and supplementing a reading speed of a main storage device ; a flash controller designating a location to which the data stored in the flash memory is written ; and a main controller calculating an area ratio of the flash memory according to the operating status of a pc , controlling the flash controller , and reestablishing the area ratio between the boot area and the cache area .