I've setup quite a few computers with mach3 that are running mills, routers and lathes, and i always say to the owner of the machine this.

DO NOT use the computer for anything else other than running the machine.

DO NOT put a virus protector on the computer

DO NOT use a wireless keyboard and mouse

DO NOT connect to the internet



It's running a machine that has the capability to cut materials that are harder than you. So if you're near the machine and a program decides to activate the parallel port, the machine will not stop if your hands are in the way.