|If you can hear the laptop running normally but nothing on the screen, the backlight may need replacing.|
Look closely at the screen whilst shining a torch on it. If you can see a faint image of Windows then you need to get the backlight replaced because the existing one has blown (just same as a light bulb blows when it's worn out).
It's a DIY job if you know what you're doing, otherwise take it to a laptop repair shop.
message edited by phil22