A method of controlling a display apparatus, the method comprising: receiving a user's voice to be used to control the display apparatus (S910; S1010); and transmitting the user's voice to an interactive server (S920; S1020) while identifying whether the user's voice corresponds to a pre-stored command in the display apparatus (S930; S1030), wherein, in the case that the user's voice does not correspond to a pre-stored command in the display apparatus, the method further comprises: receiving control information and first guide information from the interactive server (S950; S1050); and performing a function of the display apparatus based on the control information and displaying first guide information (S960; S1060), wherein the first guide information guides the user to use a pre-stored command capable of causing the display apparatus to perform the same function as the display apparatus has performed in response to the user's voice, and wherein, in the case that the user's voice does correspond to a pre-stored command in the display apparatus, the method further comprises: searching for control information which corresponds to the pre-stored command; and performing a function of the display apparatus based on the searched for control information (S940), wherein the user's voice is transmitted to the interactive server regardless of whether the user's voice corresponds to a pre-stored command. receiving a user's voice to be used to control the display apparatus (S910; S1010); and transmitting the user's voice to an interactive server (S920; S1020) while identifying whether the user's voice corresponds to a pre-stored command in the display apparatus (S930; S1030), wherein, in the case that the user's voice does not correspond to a pre-stored command in the display apparatus, the method further comprises: receiving control information and first guide information from the interactive server (S950; S1050); and performing a function of the display apparatus based on the control information and displaying first guide information (S960; S1060), wherein the first guide information guides the user to use a pre-stored command capable of causing the display apparatus to perform the same function as the display apparatus has performed in response to the user's voice, receiving control information and first guide information from the interactive server (S950; S1050); and performing a function of the display apparatus based on the control information and displaying first guide information (S960; S1060), wherein the first guide information guides the user to use a pre-stored command capable of causing the display apparatus to perform the same function as the display apparatus has performed in response to the user's voice, and wherein, in the case that the user's voice does correspond to a pre-stored command in the display apparatus, the method further comprises: searching for control information which corresponds to the pre-stored command; and performing a function of the display apparatus based on the searched for control information (S940), searching for control information which corresponds to the pre-stored command; and performing a function of the display apparatus based on the searched for control information (S940), wherein the user's voice is transmitted to the interactive server regardless of whether the user's voice corresponds to a pre-stored command. <EOS>