Is Civ3Complete installed
outside C:/Program Files/ ?
(It should be, to avoid the VirtualStorage of save-files etc.; on my machine, Civ3 is installed in D:/Games )
Is Civ3Complete being run directly from the
.../[Civ3]/conquests/conquests.exe file ?
(If you used an installer-wizard — or GOG Galaxy — to install the game and make a shortcut to it, the shortcut's filepath may not lead directly to the game executable; if so, you should amend the filepath accordingly, or make a new shortcut yourself by locating and then right-clicking on the conquests.exe file)
Which version of CAII have you tried to install ?
(I have version 2.0.5038, which I
think is the version which was originally dated July 2006 in the downloads-database, but was
updated as recently as 2013; the newer version from October 2016 — 2.0.6147(?) — was designed to be run on Win10, but I don't know how well it works)
Is CAII installed outside C:/Program Files/ ?
(On my machine, CAII is also installed in D:/Games)
Have you got the correct version of .NET installed that your version of CAII needs ?
(With respect to the 'older' version of CAII, I saw references in the CAII thread to both v.1.1 and v.3.5, )
(Apparently multiple .NET versions can be installed simultaneously, so if you don't already have v.1.1 — or 3.5 — adding it shouldn't break anything; if I understood correctly, the newest version of CAII doesn't need a separate .NET installation)
Is CAII (Properties) set to run as Admin ?
(Yes)
Is CAII (Properties) set to run in WinXP SP3 compatibility mode?
(Yes)