We need more information in order to assist you, groegrot.
What happens when you press your power button? any lights? does anythingat all display on your screen at ANY time?
Today it starts after several attempts on start button and after some surfing (netbank -news time) it shutdown suddenly and abruptly with black screen ! May be its my y HP Artist Edition notebook and not Win7 ! Luckily, I have spare PC, a Linux Ubuntu