if it is dark from switching on and the same in bios that is if you can read the bios setup key and you have checked the contrast and brightness settings usually fn key then a key on the top row of your number keys. Then probably your laptop display has gone faulty you could try hooking up a normal crt or lcd monitor to the monitor svga port on the laptop and if the display is fine goosed laptop lcd you can get replacement displays but cost about ÂŁ70 15" without fitting so might be a case of purchasing a new laptop or seeing if you can claim on your house hold insurance if laptop not under warranty sorry.