Unity 5.1.1f1 blank screen ?

Just started unity today and downloaded the unity 5.1.1f1 version and installed, but after i run it, it just shows blank screen with nothing on it as the picture shown , i tried to reinstall but still not working , any solution ?

 

It's a "little bit" late but maybe it'll solve someone's problem so:
If you're using multiple graphics cards (e.g. intel + dedicated one just like in most of the laptops) you might have this issue.
here is my solution for this:
choose the dedicated graphics card for unity engine. You can do this using the control panel of your graphics card's brand.