Such a problem, when you start UE4 24 version, a black screen appears and nothing else. Tried to update the driver , rolled back the problem is the same. Downloaded version 25 , the problem is the same. Now it started once, but when you start the project itself, the black screen appeared again and nothing else happens, when you start it again, everything is new.link text
Sounds like a bug report. They changed the bug reports to not be on Answerhub anymore but I think they are now at issues.unrealengine.com