Uninstall all traces of the app

Hi,
Installed, then uninstalled the WD Anywhere Backup sw on my MacPro. When I try to reinstall it, I get the error message that a newer version of this software already exists on the disk. I used the uninstall program to remove the app. I can't find any remnants on my disk. How do I uninstall all traces of the app so I can reload. Thanks, J