Iphone 5s My screen has gone blank but back light is on and itunes wont recognise. please help

I updated my iPhone 5s to ios 9.0.2 last night. Today ive had the screen crash twice, the swipe to open not work and now the phone has crashed completely and is on a blank screen with the background light on... I hard boot and the light goes off and comes back on again so its doing something but iTunes will not recognise the phone and wont restore it either... Please help