Excellent!
To run NCS in the background run NCS as a service. Read this guide Using Netcam Studio Service
You cannot run NCS Service as the same time as NCS X, blue icon, since they use the same code.
Now use NCS Client, red icon, to access the program.
Program closes can be two things; you use a cracked version 
or it is a Windows update that cause problems that was releases for some weeks ago. Several users had problem with that. Make an update of Windows so you have the absolute latest ones.
When you have bought the licenses I can help you to set up the magic stuff so that you can use the mobile app. If so, I need access to the computers with TeamViewer.
-Henrik