I need help

I have avast saved to my desktop. I have double clicked it and then hit run. Then I click next. It goes thru a bunch of stuff. Then it ends with there was an error while changing the product configuration.

Hi, welcome to the forum.

Is the item you have saved to the desktop the Avast installer (normally downloaded via Download.com,) ~300Kb, titled “avast_home_setup.exe”?

What is the Operating system, what other security apps are installed, what was the last AV installed?