The game starts, I see the video, then I may or may not see "Initializing Globals" and then the application crashes with the prompt to troubleshoot the application and then close.
HOI2 and HOI2 Darkest Hour and Armageddon have the same problem, but are two separate installations (two different setup.exe).
The readme says HOI2 Darkest Hour seems to be 1.2, while HOI2 seems to be 1.3a.

The official patches don't work, says the game is not installed.

HOI1 works fine.

Win7 64bit

All compatibility options don't work
Reinstall DX10
Windowed mode
Reinstall of the games
Reboot
I also tried installing only one of the two versions

Any ideas are welcome, except to use the Galaxy Client.

This game is not compatible with the latest radeon drivers.
Last known good version was 15.12
https://forum.paradoxplaza.com/forum/index.php?threads/how-to-get-dh-to-work-on-amd-video-drivers-win7-or-win10.968203/
driver download link: http://www.guru3d.com/files-details/amd-radeon-software-crimson-15-12-driver-download.html
Use DDU before: http://www.wagnardmobile.com/forums/viewforum.php?f=5

OK, time to start reading :)
http://www.paradoxian.org/hoi2wiki/index.php/Main_Page
http://www.paradoxian.org/hoi2wiki/index.php/UK_strategy


The save games work a little 'funny'?
Can I actual save the game, then load it and choose a different country than the one I saved it with?

i.e. I save as Soviet Union, raid other countries, then save and load the save as United Kingdom and forgive everything to the Communists, plus inviting them into the Allies* :D

Or I am about to lose a battle, save, reload as my enemy and send all the troops away from the border?

*well, not really possible, because of the many other countries and their relations, but hey!

Yes, of course.

Thank you, I still did not try it out...

It seems this game is like many say a spreadsheet with graphics, for you to manipulate and test things.

There are also a lot of commands to manipulate data ingame, like you are the dungeon master and provide the setting for the parties :)

Uhmmmm... I don't really agree with this, but I suppose I have more experience with the game.
The ledger is useful but not really essential: tooltips are what's really important. They provide extremely useful information.
A few parts of the game can be automated (like trade in DH).