On April 15th, 2015, Erebus 214 said: "In case anyone is stumbling onto this. GoG now offers the Windows version as an optional download. Once you install this, add the /NWC (Like this: "C:\Heroes of Might and Magic 2 (Win)\HEROES2W.EXE" /NWC) to the shortcut like you normally would and then press F4 in game to switch to windowed mode."

Does someone have a link to this?

Which "this" do you mean? Based on the date and attribution, this is the post from Erebus214, this is the download for Heroes 2 Windows (must be logged in to a GOG account that purchased Heroes 2), and there is no possible link for the shortcut because it is in your Windows Start Menu, not on a website. Erebus meant you should open the standard Windows interface for modifying shortcut properties, then change the command line that the shortcut runs by appending /NWC at the end, save the shortcut, and launch it. The change only needs to be made once. Making the change may require administrator rights if the shortcut is for All Users instead of only your user.