You don't say what Windows you are running or what the update was, but it's almost certainly a Windows Update problem.
It's known to happen that you can get a black screen following a windows update, but it's easily fixable.
See this: https://www.howtogeek.com/425382/how-to-fix-a-black-screen-after-updating-windows-10/
(I've moved this from where it was orignally posted on an old thread and changed the title).