[XenonSurf]

For problems with Win10 see above. You must start SH3.exe in Win XP compatibility mode and Admin rights (right click the shortcut and set it up).

SH3 doesn't support 16:9 resolutions, so you must use a Widescreen mod to display interiors, maps, periscope etc. in 16:9, wether you are using other mods for SH3 or not. Larger mods will require the 4GB patch.
In addition, you may have to change your grafic card scaling options to 'Fullscreen by GPU' in order for SH3 to start at all with the correct rendering. On my Win7 I have to lower my desktop resolution before starting the game, it will not start otherwise.

There are several Widescreen mods available, some of them are mod-specific, others are generic, so take a look in the SH3 mod forum section and use the Search with 'widescreen' keyword searching the titles only.