If you alt-tab out of the game and then back again, does that help? Do you still get sound when the screen goes black?
Have you browsed the technical forum looking at other topics? Nobody else has had this problem that I recall seeing, so I'm not sure what to suggest.
Check if there are files called debug.lst or error.txt in the Beyond Divinity folder.
I assume you ran the configuration and tried changing the resolution or disabling fog? Did you try playing with the graphics options in game?
Have you learned deathblow or another similar combat skill that could be causing a problem when it kicks in?
Try deleting the files in the dynamic folders;
'..\Beyond Divinity\Acts\Act1\Dynamic', '..\Beyond Divinity\Acts\Act2\Dynamic', etc.
These folders are used as a cache for the game. Files are created / copied there from the save game folder when you load, and written / copied to those folders when you save a game. The files will be re-created as required the next time you start Beyond Divinity. If there was a corrupt file in those folders, deleting the files should fix the problem.
Have you tried doing a clean re-install of the game and patch?
Zip or otherwise backup your saved games folder to another location first, just in case. Each save is a separate subfolder in the '..\Beyond Divinity\savegames' folder; the 5 'bd_act#_start' folders are created/updated by the game/patch, and do not need to be backed up.
Un-install the game, re-boot, in Windows Explorer browse to the 'Beyond Divinity' folder and make sure there are no files or folders remaining, except within the 'savegames' folder (though the 5 'bd_act#_start' folders should be gone). After that, shut down all non essential programs (especially anti-virus), re-install the game, re-boot and shut down all non essential programs again. Run the game, and maybe start a new game to see if you continue to get crashes during fights. If you saved any games in the patched version, they will not be playable in the unpatched game version. After that, install the patch again, then re-boot, shut down all non essential programs, start the game and see if you still have a problem.
Do you have any other DirectX games, and if so are they having any problems?
Have you run a Scandisk or defragged your hard drive lately?