Hi. I had to reload the os. Reinstall dopus. I might have Preferences|File|Backup configuration but not sure.
Where would the default location for the backup file be?
Where would the settings be if I didn't back the config up?
I did copy my complete %appdata% folder to external drive so I'm hoping it might be in there somewhere.
Am I in luck with this or SOL. 
If you did a backup to the default location, there would be a .ocb file in your Documents folder.
If you have %AppData% copied, the settings will be there under Roaming\GPSoftware\Directory Opus.
(There are also a couple of other folders with more minor settings, described in How to backup or locate your Opus configuration (Simple) )
The %appdata% location worked! I just shutdown dopus and copied the whole folder to new machine and started it backup and worked like a charm.
Thanks @Leo