Well, not good. Just to be clear, NCS will not start either with NCS Service or NCS X (Server with console) so you cannot access any settings. From your description I think you have done what you can. A new installation of NCS works and that the problem is in the Server.config.xml file. Most likely the server.config was corrupted at this Restart. Did you just Restart or did you Exit/Stopped NCSX/NCS Service first and then made a Restart? We have had this problem once before and you can read about that in the post link below, but I am not sure it helps here. In that case the schedule for motion detection and recording was messed up and could be fixed.
So, if you don´t have a backup there are only these alternatives as I see it:
-if you can start NCSX remove the schedules for MD and Recordings for all cams and Save these settings and start again.
-if NCS crashes and cannot even start I only see that you start all over with a new version and add the cameras again.
-Server.config is an xml file and if you have that knowledge maybe you can go in an edit out schedule for MD/Recordings, but ........
Problem with a Restart is that Windows just END process and with a real-time system with open files you never know what happens. In earlier version of Windows at a Restart Windows made an EXIT on all running programs which was much better.
Sorry for this, but it is not much more I can do here.
When you are done with this and maybe have the time I am very interested to know about the server. You have 40 cams running on Server 2016. 40 cams is a lot so I am a little bit interested to know what hardware you use. Mainly the CPU and resolution of the cameras. Is it VGA or HD cameras?
Thanks and good luck,