Try right clicking on the .EXE, Properties
"Run as Admin" + "Windows98/XP Compatibility" (+ "Disable Scaling" + "Color Rendering 16bit")

When the Game starts for the 1st time, it tries to run in full screen (not windowed) mode at a resolution of 640x480.
Some modern graphics cards and monitors don't like this.
(now often the minimum supported native resolution is 800x600 or even 1024x768)
You can only change these settings from the Mission Menu, but it does not reach it.

The Game saves all settings in the Pharaoh.inf binary file.
There are special .INF sets for changing game settings bypassing the Menu.
"Resolution Switcher EXEs"
"Windowed mode On or Off EXEs"
sourceforge.net/projects/xjdhdr-random-code/files/Game_related_files/City_Building_Strategy_Games_Series_files /

To run Windowed Mode, it is very important:
1) Color Rendering equal 16bit;
2) Scaling equal 100%;

During game development, Color Rendering was 16bit (Today 32bit);
(the eye of an ordinary person almost does not see the difference)

If you have a laptop or 4K monitor or TV.
Scaling over 100% (125% or 150%) is often used at high screen resolutions.
(this is to make the elements larger and the text to be readable)
Because of this, the picture or buttons are displaced, the mouse click does not fall.

For Windows 10, it is possible to set options only for the Game
(to avoid changes to the entire System)
Right click on the .EXE
Properties =>Compatibility =>LowColorMode =>16bit
Properties =>Compatibility =>HighDPISettings
check the box OverrideScalingBehaviour and "Application"

For Windows 7, you will have to set options of the entire System
Start =>ControlPanel =>Screen =>Resolution =>AdvancedSettings =>Monitor =>Color Quality =>16bit
Start =>ControlPanel =>Screen =>EaseScreenReader =>Small-100%

Overlays are known to interfere with the Game
(we are not talking about overlay-filters from the Game)
Disable overlays or close these programs:
- AMD GPU (delete GPU gaming profile)
- Nvidia GPU (GeForce Experience, Shadowplay as Share)
- AfterBurner, RivaTuner
- Origin
- Discord, Skype
- Windows Xbox
- Steam? (Steam overlay doesn't seem to interfere)
- other
Shadowplay, known as Share, must be disabled in the GeForce Experience Settings Panel.
Closing the process in Task Manager will not disable Shadowplay!

There are known cases when Video(*.smk) crashes the Game.
Try renaming the "/smk" folder
Sometimes the Game works but crashes when trying to play a Video.
This is due to the fact that the Video briefly changes the screen resolution to fit, which may not be available for your monitor.

You need to install DirectX 9.0c on the system
DirectX 9.0 with Runtime Pack (June 2010)
www.microsoft.com/en-au/download/details.aspx?id=8109

Looping audio problem
When you have more than 2 speakers (2.1 or 5.1 or 7.1 sound)
Older games don't know what surround sound is.
Also, modern sound cards can work in surround sound emulation mode.
Download, unpack and copy-paste with replace to game folder.
www.indirectsound.com/downloads.html
Try v12 (EAX=ON) or v14 (EAX=OFF) or v15 (noX3DAudio)
This dsound.dll replaces the native one from DirectX, like a wrapper, reconciles the old with the new.

It is also important for C3 to run in Win95/98 compatibility mode.
Renaming "C3.exe" may cause problems with sound playback.
Spaces and Unicode (umlauts, cyrillic, hieroglyphs) in the path to the Games folder can lead to missing sounds.

Windowed Mode with DXWnd
www.gog.com/forum/caesar_series/caesar_3_wont_launch/post5
www.reddit.com/r/impressionsgames/comments/5kwbzx/how_to_get_caesar_iii_to_run_in_windowed_mode_on/
This method allows you to bypass some of the rules:
- removes window frame, which is so annoying for many in native windowed mode;
- drag the Game Window to another Monitor (mouse dont stops working);
- bypass "noWindowed" bug in widescreen patches;
- bypass NOT 16bit in Windows 7;
- (maybe, Scaling NOT equal 100%;)

More
steamcommunity . com/app/517790/discussions/0/3185737486658301180/