My screen has resolution 1366x768, so the most suitable resolution in game should be 1024x768. All 3D stuff in this resolution is displayed correctly, but menu, subtitles and windows with dialogues are not. After changing the resolution to 1280x960 everything seems to be displayed correctly, except that the game screen is a little smaller.

Install the latest GPU drivers.

I have them installed, so it's not the matter of outdated drivers.

Try using the WSGF widescreen fix; this supports most common resolutions.

I tried but it doesn't work. I have this patch.dll error that was mentioned in "Widescreen Fix" thread.