The fix is really simple but I had to do some research before, simply open the NVIDIA Control Panel and go the “Manage 3D Settings”. TIP FOR THE OWNERS OF NVIDIA CARDS – Sometimes you might see during the game of the vanilla Zero Hour and mods that the graphic is flickering and it becomes unable to play after some time.
While zoom is ok, you might also need some other tweaks like custom cursors, Widescreen GUI and classic icons with hotkeys visible.
Simply change the Resolution field to support the 16:9 like Resolution = 1280 720 and save it).
MaxCameraHeight to 510.0 to support the widescreen resolution to it’s finest (remember that first you have to change the resolution in options.ini that is located in My Documents/Command and Conquer Generals Zero Hour Data. You put the GameData.ini to the Your Zero Hour Folder/Data/INI and change the following data
