Hi all i just bought Haegemonia:Gold edition and was wondering how do i change the resolution to 1920x1200 as there is option to change it to this res in options,thanks all

Haegemonia only seems to support 4:3 aspect resolutions - if the option is available in game, try running it at 1600x1200. If that option isn't showing and you have a nVidia graphics card you could try adding 1600x1200 as a custom resolution in the nVidia Control Panel and see if that enables the option ingame (I'm not sure if you can do this with the ATi / AMD Catalyst Control Center).

I've read that running the game at resolutions over 800x600 can cause issues with GOG's version of the game, so it might be best to stick with that resolution until the issues are fixed.