I think I finally got this working. This is one stubborn piece of software, isn't it?
In any case, I deleted everything again. I uninstalled then reinstalled Microsoft VC++ as directed in another thread. I went into the Lorby Addon Organizer and eliminated all of the FSDT addons with that. I went into the control panel and uninstalled all of the FSDT software. I eliminated all of the FSDT folders and files from Program Data. I went into the Program files and deleted the Addon Manager. I made sure both my security suite and Windows Defender was turned off. Then I reinstalled KLAX from scratch. It wanted me to install GSX 2, which I did. Finally, I reinstalled KLAX, and it is working.
Maybe this will help another user.