I have Windows Vista 32bit. I have installed game and push "Launch Black Gate". Dosbox starts running but then shuts down. I went to directory where game is and tried "Graphic mode setup" but it says "Error game not installed".
If someone can help me step by step?

More of a workaround, I had the same problem and installed Exult and now Ultima 7 works fine. I used the guide here except I didn't install the avatar pack.

Try running the "Graphic mode setup" app from your start menu instead. Exult is cool and all but I do not recommend it as its not the original game engine. There are many subtle differences from the original.

Same thing happened with me, don't know how to make the graphic mode thing work but you can manually make the same changes to the dosbox ".conf" file for Black Gate and Serpent Isle in their respective game directories to change the graphic settings.

As fluxrez mentioned you must run graphic mode setup from the Start Menu. Running it from the game's folder does not work because it needs to be launched with the parameter set in the shortcut.

The same goes for any and all other GOG releases that include the graphic mode setup tool.

Not sure why I didn't think of that, although I haven't installed anything in a while. Worked for 5 and 6 too. Thanks.