my win 7 screen went blank asin black blank, how do I fix it

[ife]

i was work and my computer screen went blank and has not show seen then pls how do i fix it have tried to format it but still the same

 

[hang-the-9]

Laptop or desktop? No image at all when you turn on the compter? How did you try to format it if there was no display? Did you try another monitor with the system? Power lights and fans come on?