You should look at the system logs. You will see what has been loaded
and run, what is running, and feel more secure. Nothing is run that you
didn't set to run by installing applications. Installing by itself is
not a method to make an application to run in the background. That takes
much more effort. need proof? ever tried to have an application run at
startup? Easy peesy in any MS program, not so easy in Linux, and that is
the plan to keep your info safe.