You should see all cams in NCS. The only thing that happens when you run NCS free version is that you have a red banner over the video from camera 3 and up. The IP cameras can only deliver one video stream at the time so run NCS or webcam7.
What worries me is that installing 1 Foscam works fine, but installing 2 Foscams gives you problems. Does it behave in the same way in both Webcam7 and NCS? When you install 1 Foscam and the Edimax is works fine? Even if you have 5 identical cams like to Foscam they are differentiated by the IP number.
Since it is random it must be something that are interfering with the Foscams and makes the software confused. Especially, since 1 work, but 2 no. Do you have something else running on the computer that can interfere with port 554 or something else on the LAN that can cause problems?
The uninstallation keep the configuration files. This is important when you do an upgrade so you do not need to setup the software again. As you say a good idea is to start all over and do a clean installation, remove ALL files including config files. Do this:
- first use the installation program to remove the program.
- go to C:\ProgramData where you have the folder webcam 7 and Moonware. Remove the content of these folders and then the folders itself. The folder ProgramData is a hidden folder so need you need to make that visible first.
- in C:\Program Files (x86) you have folders for Netcam Studio, Webcam 7 and also for the Moonware Universal filter. Remove the folders including its content.
- now, you can install again and start all over.
If this do not solve the problem can you make 2-4 Foscams public so I can install them on my system? I see that you use ddns already. I sent you a PM so we can exchange information. Also, very important is that these cameras deliver only 1 stream so you cannot run NCS, Webcam7 and IPcam Viewer at the same time! It might work, but it is not a stable solution.