Could you be more specific? Does the Launcher not load? Is there an error that pops up that stops things from loading? Or can you get into the game and create a character, but it won't load past that point?
Also, if you could show me your dxdiag
so we can see if it's something that may be outdated. If that isn't the case, we can try suggesting other things to find a fix once you've given more information about the issue.