It does have to do with the graphics settings. I bought a newer, better card and I got the black screen. Spent most of a day trying to fix it. Finally, I uninstalled the game. I scanned my computer for leftover traces of it in the registry. I mean I REALLY wanted it gone. I then found that the SimCity folder was still there in My Documents. I deleted that hoping it would delete my graphics profile. It did. When I reinstalled the game, it complained that my card was not good enough to run it. Still, the game worked. I set it to the max on everything, saved it, exited just to double-check, and started the game again. I works beautifully.
So, in summary, dletewherever it is keeping a file telling it about your graphics card.
I had to delete my SimCity folder in Documents.