Downloaded newest version of Mach 3 from Artsoft to a thumb drive.  Plugged the thumb drive into machine computer and double clicked on Mach 3.  Now I have two versions of Mach 3.  The old with all my configuration (licensed copy) and the new (licensed copy) with no configuration.  The forum suggest that when updating, the new version would overwrite the old and configuration would be automatic.  I have everyting backed-up.  Little help please.  Thanks

Your old version must have been in a folder  or location other than the default or you chose to install the new version to a different location.
Simple thing is just copy the xml from the old folder over to your new folder.
Hood

Yes, I believe the old version was in a folder which I have copied to a thumb drive in it's entirety.  There are several xml's in that folder.  Where is the default location of Mach 3 intended to be? 

C:\Mach3 is the default location

Just copy over the xml for the profile you used, for example if you used the default mill profile it will be called Mach3Mill.xml

Hood