Blizzard or Warzone is not working:

I started the battle.net app, i pressed start, and at first it gave me a DEV ERROR 6466 (DirectX encountered a problem and could not recover) . Did several steps to try to fix it, this error and it did not appear any more but everytime i press the start button on the battle.net app it says update. I press it, starts updating and then crashes and gives me error- BLZBNTAGT00000BB8.
Can anyone help?