Depending on whether you've logged into Windows 10 or not, a black screen could mean a variety of things.
Check your internet connection and restart your PC in Safe Mode if you haven't logged in or Windows 10 hasn't booted. (Press and hold the Shift key as your machine boots to enter Safe Mode.)
If the screen went black after you logged in, unplug all external devices and, if that doesn't work, boot into Safe Mode as described above.
If the issues persist, you should contact Microsoft for assistance.