You can change the registry values as follows (Take a screenshot or backup first):
HLKM\Software\Quest\GPOADmin\VCConfig\DataSource (Clear the value)
HLKM\Software\Quest\GPOADmin\VCConfig\ServerName (Clear the value)
HLKM\Software\Quest\GPOADmin\VCConfig\UseSQL (Change from 1 to 0)
Restart the GPOADmin Service, and log in with either the service account (on the service in services.msc) or an Enterprise Admin account.
The configuration wizard will launch, since there is no configuration present.
Once you connect to the database in the first step, it should autofill the rest of the data from the database (backup storage location and Admins/Users).