Many Black Isle games have 'config.ini' files in their folders. Perhaps looking at that may provide you with more options (if it has one) such as a Windowed Mode. If there is a file (and it's similar to other ones) it will show a list of options followed by a '1' or '0'. Changing the number enables or disables a function.
Sometimes graphics issues are fixed in the windowed mode as the monitor's resolution isn't changed. The game can say it runs on 800x600 but run on a different one (or it's forcing your monitor to go to a different resolution- this happened to me with IWD1).
Even if you set your desktop resolution to 800x600, the monitor will automatically change for any videos or if the game demands a different resolution.
Good luck. I hope that helps
