Hi, Thanks for the advice all, I have noticed I have several Mach3's listed in the Add/Remove Software dialog and so attempted to remove all.
I have loaded a fresh install of Mach3 in a new folder called "Mach3New".
I now have Mach3 and LC latest versions working ok so it looks like It's my computer that's buggy.
I still have an extra version of Mach3 in the Add/Remove Software dialog but with no file size or date. As things seem to work ok I'm reluctant to play anymore.
Thanks again for pointing me in the right direction.
Apoligys for throwing stones, cleaning own house now, humble pie, mutter.. mutter..