HELP - 3D CNC design & running programs & PCs.

Thank you for this but I'm not sure exactly what you mean by making it more complicated?

I am not very good at explaining things as i complicate stuff.
Get the 64 bit official ISO from here:
www.linuxcnc.org/iso/linuxcnc-2.8.2-buster.iso
Write it to a USB (not copy), use win32diskimager if you are on windows, boot the PC from that USB in "live" mode and test as much as you like, no need to install it as simulations work in live mode.

I will do that. Thanks.
One problem I have is that the cnc controller box is usb connected so I'd have to find a parallel card for it & then the compluter. (no good getting the card for the computer before I have the box connection worked out.)

USB does not work for machine control with LinuxCNC due to very bad latency inherent in it, also USB to parallel port adapters do not work.
PCI or PCI-E add on parallel port cards do work, but not always as there are software simulated ones for windows that also do not work with LinuxCNC. NetMOS or MOSChip chipsets do work, at least all the ones i tested.
If you are looking for a PC with parallel port, try to find older Dell or HP or some new-ish Fujitsu, search for "enterprise edition", no "home" or "office" edition they are not good. The good ones can be found from 50 to 150 Euro a piece.

Thank you very much. It's really good to find someone who obviously knows their business. Usually when I search I get the wantobes. I'll take note as I still need to convert the controller box as well. All prices you quote are tripple in Australia. I need to go to either the USA or England/Europe & bring home all the parts I need as carry-on. Not sure how a plasma cutter would pass customs as cary on. (: Ha Ha.

here is my video about setting up the Mesa 7i76e


Because you have a spindle, it would be a good choice if you have the budget except you'll have to rewire some stuff.
Unfortunately, there are no distributors in .AU, closest is in NZ 
carbidecutters.co.nz/
But I have bought direct from Mesa or from BigJohnT at  mesaus.com/

Where in Aus are you? I am in Brisbane.Happy to accept visitors