Hi Todd,
It sounds like there are some files and folders left behind when you tried to uninstall the application. It could be that you had the application open or something was locking the files.
Can you go to the installation folder "C:\Users\{username}\Applications\ArcGIS\Survey123ConnectforArcGIS" and ensure this entire "Survey123ConnectforArcGIS" folder is deleted.
Try and install the Connect application again after this folder no longer exists.
Regards,
Phil.