No Windows after 7 supported. No Intel graphics supported. GOG does not really support any Windows before 7.

Do you still have a problem? Remember you can contact support as long as your system is supported.

You may try something like DGVoodoo to get it working.

same here !do i really need win7 in 2019? is this even possible...

Well, it is an old game and not every game is so easy to get working on new systems.

If you hear of or read about someone who managed to fix it, I am sure GOG is very interested in hearing about it so please contact them.

i can play under windows xp service pack 2 with some lgvoodoo adjustments.

Try this small patch. It might help you.
https://verokster.blogspot.com/2018/05/cossacks-american-conquest-gl-wrapper.html

i may have found a solution
in the gamefolder there is a file named "cossacks" with registryentry as filetype
run it once and restart you pc
on my Computer it worked then fine