Why does my Lumia 532 screen appear black ( blank ) after start up?

[Windows Central Question]

lumia 532 screen appear black ( blank ) after start up

When I on my phone and input password the screen appear black ( out ) , the signal looks functioning but there is no tiles appear as normal

 

[Mwangi II]

why does my lumia532 appear blank after updating it to windows8.1?