Recent Resolution Problem- Black Screen

[GRENDEL]

My HOI 3 game worked fine until the last few days, now every time I start the HOI 3 game (and Only This Game, All others appear to work correctly) my screen goes black and my monitor says "Mode not supported, Change input resolution" although I haven't changed/tampered with the game's resolution since initial setup. I have already uninstalled & reinstalled the latest graphics drivers, restarted Steam & my PC. Also, I've uninstalled & reinstalled the HOI 3 game & tried starting the game from programs with & without "Run As Administrator".
The other games work fine & I'm sure I'm neglecting something obvious to resolve this problem.
My PC runs Windows 7 64-bit on an Intel 3rd gen i7 6-core @ 3.2 Ghz with 16 GB RAM, and 3GB AMD Radeon HD 7950 graphics card.
Has anyone else had similar problems with this game, and if so, how did you fix the issue? I had just gotten into the game & am eager to get it up & running soon, any help would be greatly appreciated. Please forgive my ignorance & thank you in advance for whatever help you can offer.

[GRENDEL]

Also... I'v tried going to C\Program Files (x86)\Steam\steamapps\common\hearts of iron 3 and opening the text file "settings" and it already has the correct resolution x=1920 y=1080 with fullScreen=yes
Sadly my game still does not work. I failed to mention that I do get Wagner's "Flight of the Valkyries" audio during my black screen so the game is running, I just can't see it. Any help would be so very appreciated, I just can't find a working solution. Thanks.

[Thraldrek]

I have the exact same issue with my game. I've tried reinstalling, playing around with certain things, going out and searching for information - nothing. I was playing a really good USA game last night and when I turned my computer on today to continue it, it suddenly stopped working again. I have no idea what to do because all I did between turning the game off and trying to start it up again today was turning my computer off for the night last night. Pisses me right off.

[GRENDEL]

Hearts of Iron 3 "Black Screen of the Valkyries" RESOLVED
Recently my Hearts of Iron 3 game (I have the HOI 3 Collection with all DLC) just stopped working out of the blue. There was no problem getting to the game launcher window but after that all I could get was my monitor falling to black screen with the message “Mode Not Supported. The Resolution Is Not Supported On This Monitor- Please Change Resolution" although I hadn't changed/tampered with the game's resolution since its initial setup. However, I did get Wagner's "Flight of the Valkyries" audio during my black screen so the game was running, I just couldn't see it.
This is a collection of solutions I uncovered from both the Steam & Paradox Interactive forums before my problem was eventually resolved by a gentleman from Paradox support. The solutions were scattered, varied & not terribly easy to come by, hence, the compilation of this list. Even if only the last solution helped my issue it could easily be another that helps you. Please forgive me for not crediting each solution, as I said they were taken from different sources & many had multiple authors, variants or were just obvious.
1) Verify game cache from the properties menu in your Game Library.
2) From your Steam Game Library, Right-Click your HOI 3 game & select “Properties”. Under “General” Disable the Steam in-game overlay by unchecking the appropriate box & restart game.
3) Try starting game from program files both normally & “Run As Administrator” (the location should be something like: C\ProgramFiles(x86)\Steam\SteamApps\common\Hearts of Iron 3 and the game application labeled “hoi3” or hoi3game” Right-Click to run as Administrator)
4) Restart computer
5) Uninstall & Reinstall the latest driver for your Graphics Card with a fresh computer restart.
6) Update Directx & Install (or reinstall) Directx 9.
7) Uninstall & Reinstall Steam.
8) You could try following this procedure: a) Click on the Windows start button in the tool bar.
b) In the search window write %APPDATA% and hit the "enter" button.
c) Locate and open the folder labeled "fatshark".
d) Go in the "fatshark" folder and delete the "wotr" folder with all files. (Yes, HOI 3 has a folder titled” wotr” for some reason, or at least mine did- Paradox makes “War of the Roses” yes, but not having that game I was very surprised to see it here- perhaps it’s a remnant of some past marketing thing.) Note: Be warned that even if successful the video and audio settings will be reset to default.
e) Restart computer, Steam, and then game.
9) Try going to: “C\Program Files (x86)\Steam\steamapps\common\hearts of iron 3” and opening the text file "settings" to manually change the resolution, in my case the correct resolution for my monitor should read “x=1920 y=1080” with “fullScreen=yes” also checked. If you’re worried you can save a copy of the file elsewhere before starting. You can/should also repeat this process with the text file labeled “settings” under Documents\Paradox Interactive\Hearts of Iron 3
10) That last one was close, it didn’t help me, but Brian from Paradox Support suggested completely deleting that "setting" text file from “C\Program Files (x86)\Steam\steamapps\common\hearts of iron 3” he assured me that it would be fine & auto regenerate. I tried it & although that didn’t work, when I also tried his procedure to the text file labeled “settings” under Documents\Paradox Interactive\Hearts of Iron 3 & deleted it my HOI 3 game finally worked. As Brian said, the file regenerated under the “Program Files” attempt. To clarify he made no such guarantee to trying that under “Documents” so don’t blame him or Paradox for that but, as far as I can tell my problem is gone, my saves & settings seem fine & I’m happy.
While I hope one of the above helps you, I cannot guarantee anything & you use those solutions at your own risk as I did before you but, for what it’s worth I can detect no ill effects from any of the above. Good luck.

[Thraldrek]

There is also a TFH.exe you can download from the paradox forums. It's podcat's executable I think? It fixes some fatal bugs I believe.

[Roran]

9) Try going to: “C\Program Files (x86)\Steam\steamapps\common\hearts of iron 3” and opening the text file "settings" to manually change the resolution, in my case the correct resolution for my monitor should read “x=1920 y=1080” with “fullScreen=yes” also checked. If you’re worried you can save a copy of the file elsewhere before starting. You can/should also repeat this process with the text file labeled “settings” under Documents\Paradox Interactive\Hearts of Iron 3

Make sure that the refresh rate is the same in both files, for some reason it was 30 in the documents and 60 in the steam folder for me, changing both to 60 fixed it for me.