P.S.

The only clickable link on the app-checking screen was a button saying: "Uninstall Updates", as if instead of installing the full Opera program, I only installed updates to it. Puzzling...

I couldn't install Opera from the Google Play Store. Don't know why, and Google has no tech. support.

From the Opera website, I downloaded the Opera .apk to the external SD card on my Zeki TBD753B tablet running Android 4.1.1 [No upgrade available!]

Using a file manager, I clicked on the .apk, and installed it with no error messages. However, checking Settings/Apps/All, Opera was "Disabled" and there was no apparent way to enable it.

How can I enable it, or reinstall a different way?

Thanks, any help would be appreciated.