Where does %ProgramFiles% take you to if you enter it into the File Explorer location bar? I believe the installer should be using that, unless a previous install went to another place.
Uninstalling, rebooting, then installing again may reset the path it uses. But not that it will also wipe your Opus configuration.
If needed, you can manually backup the configuration by copying three folders (or just one; the other two are less important). That should be done before uninstall.