Thanks again for everyones input so far.

This morning I was doing a clean install of Windows 7 32Bit, after doing a DOD wipe, on my Tablet PC, before installing all the software I need for the Tablet PC, I thought I would give Mach3 a try on that and see what happends.

So I once again installed Mach3 3.043.062, No LazyCam, No PrinterPort Driver, installed 2010 ScreenSet v1.1.4, Mach3 License.
Ran Mach3 and used the default Mach3Mill xml profile, selected the 2010 screenset from menu.
And I was still about to get it to crash.

So thats now 2 PC's and 1 tablet pc that I can get to crash in the same way.

I was at the workshop today, so I uninstalled everything to do with Mach3 from the CNC Computer, and deleted the "C:\Mach3" folder.

I then Installed Mach3 3.043.006, 2010 ScreenSet v1.1.4, Ethernet Smoothstepper Plugin ESS_v10fb2, Mach3 License, XML config file.

I have been using it since aprox midday and I have not had one crash.

I still can not work out why 3.043.010 and newer crashes, and where 3.043.006 works fine.

I am going to setup a VM on my home PC so that I can install multiple OS's XP, NT, 2K, W7, etc, to see what I can find out.

As said above I am up and running using Mach3 3.043.006, but I want to try and get to the bottom of why the newer versions crash.

Thanks again.