the Steam community often comes up with helpful guides on how to get old games patched to run in Windows 10. The same is valid for Cossacks,
However, it fells a bit short on assumptions that you don’t need the English language file as Steam’s installation is the English one. But what if you have a CD original in another language and don’t want to pay money to buy the game a 2nd time?
This is what happened to me, so let me help you out.
After installation, you are confronted with the error message “Please log in with administrator privileges and try again” which is because the copy protection driver is blocked by the security mechanism of Windows 10 as you can read in this German article
So what you need is a no CD patch. Once this has been sorted out, follow the guide on how to apply a patch for Windows 10 compatibility of the Steam guide I have linked above.
Last but not least, to change your games’ language, use the same guide, but download this English language file taken from the comment section where I requested the original author of the guide to make it available. Download is broken? then contact me if you need the file.