The main reason for this cause is the  display driver of your computer and in most cases it occur when u updates or change its resolution depth beyond the capabilities that your monitor can display(i.e.  suppose a 15′ monitor which normally can display 800X600 display at 75 HZ and if anyone increases it at 1074X768 or more at the same refresh rate the next time it is restarted it will show a black screen)

The solution for it in many cases is very simple if you follow the steps carefully. (It will be better to have the copy of your Graphics hardware driver ready if windows needs it in the final step but usually it is not required as windows keeps the inforamtion of every driver in its database)

1. Restart your computer and press F8 before windows logo display appears. (means start your computer in safe mode if u know how to do it)

2. Choose Safe mode option ( in this case none of your display driver will be loaded and colours of your screen will be very limited.)

3. Open your System Properties  (Right click “my computer” with mouse and choose properties)

4. Go to Hardware Tab and choose Device Manager.

5.  with in the next pop up windows appears locate display adapter and removes everything find and restart.

6. Now the next time when it will restart the original driver will be  automatically restored with the display setting compatible to your system.