What kind of graphics card do you have and what is the driver version?
I use a laptop and my video card is a Nvidia 9600m GT and I updated the driver to the latest available when I first started having problems: Nvidia 266.58.
I already checked my sound as that was the first thing I read online that could cause crashes. I did notice that it crashed far less in a day time setting then at night using lightning spells and that the slower fps spells i.e., fire and ice, have no problems what so ever, so I'm thinking it has something to do with fps 'burst' for lack of a better term that my video card or cpu can't handle. I'm just not sure what to do about it if anything if that is the case.