“Control Panel” doesn’t provide “Add/Remove programs”, but there’s an entry “Programms and Features”. After a right click on “Avast Free Antivirus” only “Uninstall” and “Change” are available, a right click on other programs sometimes offers “Repair”. IOW there’s no repair feature available and apart from this neither “Change” nor “Uninstall” does anything. I downloaded avast from https://www.avast.com/windows-7-antivirus and from http://www.chip.de/downloads/avast-Free-Antivirus-2017_13010163.html , both seemingly returned “C:\Program Files\AVAST Software\Avast\setup\Instup.dll is either not designed to run on Windows or it contains an error” or when doing the install from the second link, it was a repeated output from the unsuccessful install from the first link, since in the end the download from the second link was able to reinstall avast. Reinstalling avast solved the issue.
