He did say
"I can't show a screenshot of my desktop if I can't log in (besides safe mode) and no error messages"
so i assume that he is able to get visual via safe mode.
it happened to one of our computers a week ago. black screen with only the mouse cursor visible.
don't know what happened and i didn't have time to mess with it. so our server took care of it.
i restored it via an image we have on our remote installation server.