I am so sorry to ask here but I don't understand (and don't much like TBH) the Steam forums, and when I did look for this particular game, there was no recent posts leading me to believe it's pretty much abandoned. I did go ahead and post a question there, but it wouldn't surprise me if it were months or even never being answered, so I want to try here.

The game is March of the Eagles (Paradox) and I did a search here but couldn't find it. If it is sold here, then just forget the below questions, let me know it's sold here, and I'll just buy it here and be done with it. But I couldn't find it here and very much wanted to try it tonight.

But I can't get it do anything. I've downloaded it twice, and checked the file integrity twice (and both times said everything was 100% fine). But when I click on it to PLAY, a box comes up with a CD key in it (see Capture 1). So I click COPY TO CLIPBOARD and then click PLAY. Then a big white box comes up with Marth of the Eagles on it (See Capture 2) and a few smaller gold boxes in there. One of those boxes says REGISTER, so considering the CD key I figured that's what I need to do. So I hit that button and get the message shown in Capture 3. So then I just try and click on START MARCH OF THE EAGLES and then everything just goes away... pooof. (See Capture 4).

Can anyone help me play this game?

I don't know about that particular game, but paradox CD keys are usually for forum registration only. So you can enter Paradox Plaza, create an account (if you don't have one already) and enter that key to tell the forum you own that paradox game.

You can try asking over there also.

Okay, thank you. I guess what you're saying is (and I think you're right too since I get that error message when I try to hit the REGISTER box) is that the CD key really has nothing to do with whether the game is running correctly or not. So it's likely either a windows 10 issue or some sort of other issue I guess unrelated to the CD key.

So frustrating. If these games don't work on modern systems, that should be CLEARLY AND EXPLICITLY stated on the store page. I mean in BIG LETTERS at the top "THIS GAME ONLY WORKS ON OLD OPERATING SYSTEMS"

I just wanted to play a rather simple but in depth strategy game tonight, one I hadn't played before, and did some reading and this one sounded perfect. It was sort of a "cut down" from the other Paradox titles, easier to learn and play, and yet still has some good depth. Really really wanted to try it.

Please GOG, can you get it here?

Looking this game up, it was released in 2013. There really shouldn't be any reason it doesn't work on the latest OS. It could possibly be something specific to your PC like drivers.

Not many votes for it on the GOG wishlist: https://www.gog.com/wishlist/games/march_of_the_eagles

Well, the Steam store page does have the "System Requirements" at the end of it, also listing the supported (or at least minimum) Windows versions. For this particular game, it says: OS:Windows XP/Vista/7.

Then again, I recall sometimes that Steam store page system requirements are misleading, e.g. with some older games it might mention just e.g. XP or Vista as supported OSes, while I am pretty sure the game should be supported on newer Windows OSes too. It does state those are "minimum system requirements", so I am unsure how the end-user is supposed to understand that: that e.g. this game works on any Windows OS after (and including) XP, or that it works and is supported only in XP/Vista/7? That would seem odd though, as it is only a four years old game.

On GOG store pages it is clearer because GOG lists in which OS versions a game is supported by GOG (ie. either GOG or the publisher has tested the game on those OSes).

Also, of course your problem may be something completely unrelated to the OS version. Maybe a problem with your GPU drivers, or some missing C++ runtime blaa blaa libraries or whatever.