Hi,
if you are planning to use a parallel port then you seriously do not want ANY....stress ANY other software
than is absolutely required on the PC.
I heard it described 'when a PC is connected to and controls a CNC machine it is NO LONGER a PC but a machine controller'
I you follow or subscribe to this advice then there is no need for dual boot, that would be to suggest that this PC can be used
as general purpose PC. What you are inviting is loss of control and potential crash of your CNC machine.
Craig