&gt; why fix what ain&#x27;t broke<p>Because it will break eventually. That decrepit PC full of metal dust running XP that controls this here multimillion CNC mill will, given enough time, fail. Some part or other will fail, and eventually you won&#x27;t be able to find new parts anymore that work with it. Granted, for an XP PC it&#x27;s far in the future but still.<p>Besides, a Win 3.11 or XP PC won&#x27;t have a 15 year uptime, it will probably have a sticker on it reminding users to reboot it daily.