Hi, BR. Thanks for response. Good catch. I checked for other Calibre or Calibre2 folders in both C:\Program Files\ and C:\Program Files (x86)\. No other folders. So, I uninstalled again and THEN I restarted my PC (I didn't do that before). Then I downloaded again from
https://calibre-ebook.com/download_windows64, and reinstalled. The error is gone.
Thanks. Sorry for not restarting my PC before posting.
Regards,
Steve