I solved this... My mobile was dead during the night and try mny times to turn on the day after... So i try to connect it via usb to pc with zune on it, after 1 hour i disconnect it and reconnect somes times and finally my devices turns on! Another tips for this phone: when the phone and battery goes down, connect at battery charger but until the red battery symbol and nokia logo do not disappear from the screen do not press anything because this cause the "turn off bug". Sorry for my bad english, hope i help you guys!