It could be that some assets have been corrupted. Have you run the Steam client validation tool?
If that does not help, try lowering your graphic settings and resolution to minimum, and just see if it loads. Your graphics chip is middle-of-the-road, and while it may play other games well, DAO is an unoptimized beast. If it loads at minimum settings, you can then increase them step by step.
I suppose it could also be a corrupted display driver. Have you experienced crashes in any other games?