We have been using this little tool to completely disable Windows Updates for the past ~year or so now.  They just came out with a v1.1 yesterday, I believe we have been using v1.0. --- https://www.sordum.org/9470/windows-update-blocker-v1-1/ --- I was skeptical of it at first, but it's been working flawlessly on 16 rigs (although not all of them have been running a full year yet.