I once hooked up a debugger to the executable and the root cause of the crash seemed to be an access violation in one of the game's DLLs (which seems to be some sort of utility library that originated at Digital Anvil). So the game is trying to access some uninitialized memory, which wouldn't shock me, as that's a common problem among older Windows programs. The way Windows does memory management has changed over time, so while before you could be bad and still work, now it just crashes. The two options would be to reverse engineer that DLL to correct the issue (quite hard) or try to get Microsoft to put in some sort of shim for app compatibility (takes a while, can be deprioritized).

Interesting!

I've tried two fixes as explained on this page: http://www.blitzbasic.com/Community/post.php?topic=99477&post=1202630

Whether it's the ACT or the ddraw.dll files, these fixes should help quite a lot regarding perfomance issues under 8.1. However, they also seem to help launching Conquest Frontier Wars!

I'm using the ACT. With DXPrimaryEmulation set with -DisableMawWindowedMode, the game launches, but everything is black. Sound plays though, so it's 'only' an issue with the display. If you add ForceDirectDrawEmulation, you can watch the intros (which may be a bit choppy), but once again the screen turns black when you reach the menu (main menu music is playing though!).

I hope this helps a bit, considering what MrPopo wrote just above. Maybe this ddraw.dll needs some slight modification or there's another fix in the ACT which may solve the black screen issue. DxWnd, last version, may help too.

I've been trying various things that sound like they might work in the ACT but so far I've had no luck. I'm still at the point of black screen and music playing, which is a step up from before. I also gave DxWnd a shot but that didn't seem to be able to hook in; I tried running it as administrator and it could launch Conquest but it still went full screen.

Ok, I was able to get Conquest fully working on Windows 8.1 64bit with an nVidia 780 GTX video card. The only thing that does not work is the Options menu, which I don't need to use anyways.

Part 1:
I noticed that Conquest kept crashing in the nvd3dum.dll file which is the nVidia driver file. So I copied an old version of nvd3dum.dll from a Vista computer into the Conquest folder. The version of the dll I used was: 7.15.11.8586.

If you don't have an old copy of the nvd3dum.dll file you download it here:
http://www.dll-found.com/zip/ah/25579/nvd3dum.dll.zip

Part 2:
The other thing I did was to remove all the application compatibility settings for Conquest. There are two steps for that:

1. Make sure there are no settings for Conquest under this registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\InstalledSDB
Note: Look through all the sub keys {CLSIDs} to ensure that none of them are for Conquest. Delete any key related to Conquest. Note: remember to backup the registry before you delete the key in case you want to restore it.

2. Right-click on the Conquest.Exe file and select properties and go to the Compatibility tab and disable all items. Make sure to do this under the "Change settings for all users" button as well.

If you are running an nVidia video card these steps may work for you also.

If you have some other video card (like ATI or Intel) check the Windows Event log to see which dll Conquest.Exe is crashing in. It may be the video card driver dll as well. If it is you could try copying an old version of the dll for your vidio card. These steps may work for other video cards, but I only tested them with nVidia.