Civ 5 Demo problems

[Sanatorii]

So I recently downloaded the Civ 5 demo from steam to try before I buy. The first time I started the game it went all the way to the end of the opening cinematic then crashed. I edited the options to skip the opening, but after I did that the game would open up as a little black box in the corner. I can still hear game music but I can see anything only a small black box. According to dxdiag I have directx11 and at least the minimum spec to play. I'm new and just made this account, so If this is in the wrong place I apologize. What I am wondering is if this same problem would happen if I were to buy the full game? Thank you to anyone who can help me resolve this issue.