A display apparatus comprising: a volatile memory; a nonvolatile memory; and a processor configured to: receive a user input to turn off the display apparatus from a user, prior to entering a power-saving mode, identify whether a system error occurs in the display apparatus by reading a stored value related to a system stability from one of the volatile memory or the nonvolatile memory, in response to receiving the user input, in response to identifying that the system error does not occur in the display apparatus, enter the power-saving mode while maintaining power supply to the volatile memory in which execution data regarding an application currently being executed is stored; and in response to identifying that the system error occurs in the display apparatus, perform a rebooting operation after storing execution status information of the application currently being executed in the nonvolatile memory, store, in the volatile memory, the execution data regarding the application which is obtained by executing the application by using application execution status information stored in the nonvolatile memory, and enter the power saving mode while maintaining the power supply to the volatile memory, wherein the stored value related to the system stability includes at least one of a value indicating whether the application currently being executed is operating normally, a value indicating whether a system internal memory is operating normally, a value indicating whether a system driver is malfunctioning, a value indicating whether a crash occurs between running applications, and a value indicating whether a reboot is required due to a software update. a volatile memory; a nonvolatile memory; and a processor configured to: receive a user input to turn off the display apparatus from a user, prior to entering a power-saving mode, identify whether a system error occurs in the display apparatus by reading a stored value related to a system stability from one of the volatile memory or the nonvolatile memory, in response to receiving the user input, in response to identifying that the system error does not occur in the display apparatus, enter the power-saving mode while maintaining power supply to the volatile memory in which execution data regarding an application currently being executed is stored; and in response to identifying that the system error occurs in the display apparatus, perform a rebooting operation after storing execution status information of the application currently being executed in the nonvolatile memory, store, in the volatile memory, the execution data regarding the application which is obtained by executing the application by using application execution status information stored in the nonvolatile memory, and receive a user input to turn off the display apparatus from a user, prior to entering a power-saving mode, identify whether a system error occurs in the display apparatus by reading a stored value related to a system stability from one of the volatile memory or the nonvolatile memory, in response to receiving the user input, in response to identifying that the system error does not occur in the display apparatus, enter the power-saving mode while maintaining power supply to the volatile memory in which execution data regarding an application currently being executed is stored; and in response to identifying that the system error occurs in the display apparatus, perform a rebooting operation after storing execution status information of the application currently being executed in the nonvolatile memory, store, in the volatile memory, the execution data regarding the application which is obtained by executing the application by using application execution status information stored in the nonvolatile memory, and