When I try running the .jar executable a black CMD console opens and then closes for a split second. I've tried installing Java and many other things but it still doesn't work. Please help.

I recently developed a new version of the installer, that is supposed to be easier to execute.
(Because it's packaged as a native executable.)
Please try the new version,
it maybe the case that for Windows systems you get a dialog complaining that the installer could be a virus, because it has no signature - just ignore it.