[MovedGoalPosts]

hmm, no idea why internet connection sharing should not remember the settings, or drop something, but maybe it's related to the issues you also had trying to get ethernete rather than USB connectivity.

You could try deleting the entire network connection and associated drivers from the windows control panel > system > devices > hardware, reboot and reload (current version previously downloaded from the net). Have a look to at any firewall or antivuirus software you are running.

I'd have another go at getting ethernet running. Remember you must reboot the modem (power off poweron) when changing anything that is connected to it, whether USB or ethernet, and any redundant cable should be unplugged from it. You shoudn't need any ntl software for ethernet to work. On the basis that ethernet will work (and if it won't phone ntl to send you a different modem, because it should), get yourself a router. If you need a switch the number of things you are wanting to use would be better served with proper network layout.