ok what I would do then would be:
1) verify that the restore you used was the last one prior to the new install (maybe you used the lastone which would have been automatically made,) in otherwords the last version 19 backup. Assuming you checked the settings option box.
2) if you already did number one, Make sure that version 19 works!! It should. then I would uninstall version 20.
This should auto port your settings with one exception it will install the WDM driver which will ask for permission to do so, so stick around and watch your screen; Your 19 config should port over automatically. It should work.
3) If not, check your Windows sound settings, these might have been changed, but the restore would not affect these. Put them back how they were. Actually you could do this first, maybe its set on the WDM driver which has now been removed
If this still does not work and you have have reinstalled the chord stuff, I can only
guess that there is a driver conflict or registry issue. But hopefully this is not the case otherwise version 19 would not work right anymore either.
Fingers crossed, hope this works,
otherwise is reconfigure time from the ground up unless someone else has a faster way.
PS if it does work, don't get rid of version 19 for a week or so. I wouldn't mess with setting up any new zones, dsps etc until you are sure everything is ok.