My iphone doesnt work it only appears the apple symbol on the blackscreen
Yesterday my iphone didnt start I charged it even when it was already charged but it still didnt work, suddenly after a few times that I pressed the two buttons at last it worked well , I left it charging during the night buth today when I tried to use it it was black again and now before I pressed the sleep/wake buttons it only appears the black screen with the apple but it doesn't open the screen . Please tell me how to fix it beacause everything is in there and I dont have a backup!!!