Fix macbook screen goes black, but still running

Fix macbook screen goes black, but still running. How to restart macbook air when black screen ************************************************************************************ If you are really interested in my video please follow me on YouTube and Facebook …………………………………………………………………………………………………. Subscribe to my channel:    / channel   FACEBOOK GROUP:   / 411530109484518   FACEBOOK PAGE:   / itmagicsbd   ………………………………………………………………………………………………….. Background music:    / channel