Sorry if you don't understand by what I meant with & without. What I mean is:
Without: If I don’t install the 1.13 mod then the Jagged Alliance 2 and Unfinished Business won’t boot at all. They just immediately crash and I get the standard message Jagged Alliance 2 / Jagged Alliance 2.5 Expansion has stopped working.
With: If I do install 1.13 the games does boot, but they only play the sounds and music, no picture, I can here the opening videos and the sounds from the main menu but just a black screen and pressing keys or mouse clicking will not do anything. I have to hit the windows key, drop to desktop and close the game there.
As said above I find this strange as Wildfire runs perfectly without any alterations or additions.
Thanks for making that/it clear, and pardon me for my limited english language comprehension.
The issue appears to be related to playing the video format in win 8 & 10,
so you could try to copy the .dll files from the fix to your JA2InstallDir
and update the registry if not already done.
Wildfire may not cause the issue because it replaces some video with an empty file.
So you could also "replace" the videos of JA2 vanilla with copies of the empty video files,
or use empty text files(created with plain .txt editor like notepad!) with appropriate names.
(Not sure if the latter is suffiient or perhaps even required to prevent tne initialisation of the video engine)
JA2 video files are contained in \Ja2InstallDir\Data\data.slf.
The extension .slf is used for Sir Techs proprietary archive format, such files can be handled by the slfExplorer aka slfExplore.exe.
Link to dld page: http://www.jaggedalliance.de/download/filearchiv_list.php?group=7
English translation of slfexplorers german interface: http://ja2v113.pbworks.com/w/page/28862290/SLF%20Explorer%20Interface%20Translation
Open intro.slf and note all filenames in the left window,
create the folder Ja2InstallDir\Data\Intro and paste copies of Ja2WildfireInstallDir\Data\Intro\empty.smk respectively empty .txt files,
rename according to the names you noted in 1st step.
To remove the "hack" delete the folder \Intro incl all containing files.