Why isn't my screen working? Or anything at all? (s5)

[AC Question]

So starting yesterday, my phone's been blacking out (the screen is dark but the phone still responding on the buttons) Also my phone is going super slow and I have to restart it many times to even get the screen on. And when I do, I cant get into settings because it says "system updating please wait" on the notification bar resulting in me having to restart the phone again

 

[B. Diddy]

Welcome to Android Central! Did the system actually finish the update? Did you power the phone down or reboot in the middle of a system update? That's generally not a good idea.