I performed a clean windows install a day ago, and just finished uninstalling Avast after it's shortcut just appeared on my desktop. I had downloaded and tried avast previous to the new windows install, and had also downloaded and used CCCleaner. I did not install Avast through CCCleaner at that time, I downloaded it form their website. However, as I said, after a fresh windows installation Avast has installed itself. The only thing I didn't do when I installed Windows was format the drive, so it saved a bunch of data from the previous system. I don't know if formatting would have prevented Avast from doing this, but not fomatting the drive before the new system install is maybe what allowed it to come back. I would like to know how to prevent this from happening again, as I would rather not have to reformat and reinstall windows. Any advice would be appreciated.