What control software are you using are you still using Mach3 if so there are options to use a computer with a USB by using a UC100 you must buy the UC100 from the manufacture and not a Chinese copy, with the UC100 you can run your machine from any computer that can run Mach3 control it will run better than it ever has before just with this UC100
This is the manufacture there are suppliers they have that see these also
CNCdrive - motion controls