I have been using Mach 3 on my older Supermax YCM-30 knee with a desktop PC mill for a while, mostly it has worked well. Lately, I hear a beep just as the machine makes an errant move. No beep, move will be OK... I uninstalled/reinstalled Mach 3, same problem.. I can shut it all down, and the next day it's like nothing ever happened. Anyone have an idea?