I know this is a REALLY old topic but I had the same problem in the last week and here's how I solved it. If you have something similar to my configuration, it might help you.
The problem was that after the Welcome screen I had a delay of about 1 minute (or more), which is not normal, because I'm using a SSD. In the end, I checked what I have installed recently. It turned out to be a program for my sound card - Creative ALchemy. If you've installed drivers for your Creative sound card, you might have installed ALchemy as well. I did by mistake and uninstalled it, because I don't need it (no one does, ever). But the uninstall doesn't clear it all. Services remain - and removing them from the msconfig -> services fixed the black screen problem.
TL;DR - go to msconfig, click Services, check the "Hide Microsoft Services", and uncheck everything else, then restart your PC. If that fixes your problem - check what was the cause for it and bring back services one by one or five by five, your choice.
For me, it was the Creative ALchemy stuff, and I registered here just to tell you how I fixed it. Of course, clean your startup items as well. I guess you've already done that, though
Hope it helps.