Hi Carl,
I don't know if you have been able to get the version 12.5.x client software installed yet.
However, there is an old problem with the installer in version 12.5.x where when you clicked on the setup.exe in the Windows Explorer, it would show a command window for about 1/2 second and then dissapear. The workaround for that problem was to go into the directory from a command prompt. Then set this environment variable.
set JAVA_COMPILER=NONE
Then run setup.exe from the command prompt.
That might resolve your problem.
Thank you,
Kevin