You might have a problem with the cable connecting the screen to the motherboard or with the standby button itself. In any case it's a hardware problem that needs a service tech to repair.
Ok Thanks for that but can you bee a bit more specific, could it bit the back light or the inverter do you think?
Sure it could be either. But, only a PC Tech can safely open up the case and swap out components. You chance breaking more parts if you try to fix it yourself.