I don't know if it's bad form to necro a thread like this, but I feel obligated to point out for future readers that pcguy is correct and bob is not. I have had avast uninstalled for a long time, I used the avastclear program to "completely" remove it and I removed the extensions from chrome, and yet somehow when I just installed Vivaldi (another chromium browser) on my computer, even though *I did not sync it with anything*, as in it is literally a fresh install with no bookmarks, extensions, settings or anything else from any other browser, and I've never used Vivaldi before... somehow Avast Online Security and Avast SafePrice were installed on it. None of the other programs or extensions on my computer did that, this type of behavior is straight up malware.