NC v2.5.2 reinstal needed - how best to do it

[jss]

Hi Sherry,
Thanks for such a comprehensive reply. In short your solution fixed the problem fine. In a bit more detail...
Method 1 did not completely fix the problem. Some devices still remain in the Perform>Playalong dialogue which were no longer present on the machine. However it did fix what I think may be a (minor?) bug (kind of). What happens is this:-
Say we have a machine running 2.5.2 fine. Change the soundcard. Reboot. NC lists the new soundcard but still lists the old one as well. All seems works ok but do: Perfom>Playalong sound and select appropriate device. Click "Make this the default". At that point a red warning comes up in the notification area of NC (bottom of screen somewhere). After that error appears other things go wrong with various devices and warnings popup from them. Sorry can't recall the exact text of the errors. But anyway, this fixes it all...
Method 2.
This proved (for me) the best option. I simply located mididev.cfg as you described. Renamamed it old-mididev.cfg, and rebooted. After this all devices listed were correct and the playalong sound worked and was remembered as default.
Thanks vm for your help
-John