Glenn I did blunder around until I got lucky. Now it's a pretty straight forward fix if you have the original Google/Nik Collection download still on your computer. Once the upgrade is on your computer try to see if it works, if not then just install the original over the new. My computer did warn me that I had a newer version already installed, but I just pressed ahead. That's all it took just wish I had thought of it at the beginning. I would have more hair left on my head. LOL
If you don't want it and it still makes it's way onto your computer, all is not lost, just delete the new upgrade and reinstall the original and all will be well. I learned that the hard way too.