Thank you for the reply!
Mach3 Software Requirements seem to indicate that it will work with 64bit OS if you use an external motion controller that is unless I am completely reading it wrong. My question is what does an "external motion controller" do; why do I need one for 64-bit support; and which one should I purchase?
from Mach3 Software Requirements...
Laptop / 64-bit Desktop (using an external motion controller)
◦An appropriate external motion controller (options can be found on the Plugins page)
◦Windows 2000, Windows XP, Windows Vista, or Windows 7 Operating System
◦1Ghz CPU
◦512MB RAM
◦Basic Computer Skills (ability to copy/rename files, browse directories, etc)