I remember once a program forced a surprise install of AVG on me, intentionally hiding it in an array of random HIT THE YES BUTTON TO CONTINUES (What the forget is with this nonsense) None of them had to do with installing anything but I managed to catch on when it popped up, apparently I couldn't download said program from said site without downloading said AVG. I simply closed the installer but it tried to install AVG on me anyways. Despite immediately ctrl alt deleting and terminating the process it managed to pile on 3 applications onto my pc which immediately high-jacked it and forgeted with my browser. As it turns out, AVG also installs these sort of ghost apps that prevent you from uninstalling AVG or changing your browser, these programs also attempt to restart if you end their processes. I wound up having to use a batch file to ignore typical system protocol and delete those app files at the exact instant I shut the application down; then deleted all of AVG's files, then uninstalled them formally. That forgeter is no longer on my pc, and never will be. But expect to have to do some funky stuff to get it removed.
The moral being that every stuffty program will try to find every annoying way to latch onto your pc even if it's supposedly anti-virus. You will likely need to use google to find a formal way to delete it, or you can try my method, just gotta figure out if its using any special ghost programs to keep it running.