Two Machines from one PC

[A_Camera]

Cheers.
I was hoping to run them both at once. It will take me a week or so to get everything set up as I will need a mouse,keyboard and monitor next to each machine

Get a KVM switch. That's what I'd do if I were you.

but as the new PC is a lot faster then the old two put together I will give it a go and report the results

It may work but only if you are not using parallel port but some controllers.