Re: Can't get higher resolution settings in DA2
@radaghast15; goraththeelder is correct. The "Very High" textures are only available to be selected if you can implement DX11 as the renderer. Since you only have DX10, this is impossible on your current rig.
I *think* that there was a hotfix to supply DX11 software for Vista, but don't quote me on that. Google is your friend in this situation.