First of all, computer that is running CNC machine SHOULD NOT be connected ti Internet.
It might be connected to LAN, with only a couple folders, non critical ones, shared, so if any gremlin sneaks in will be safely contained
Second, when you have a working system, no further updates should be allowed (M$ is known to destroy a good working system).
My computer that is connected to CNC machine is a pure controller and nothing more than that. No unnecessary software, besides Notepad++ and some more utilities. No M$#&% Office or other bloatware. It even runs Win XP
HDD image of working partition safely stored on 2 external drives.