How stop AVG so can test Avast?

So I took the plunge and replaced McAfee with AVG. Among the byproducts is my computer works much faster. Now I'd like to try Avast, since many Geeks seem to like it. I've downloaded it, but not installed it. How do I stop AVG from running? I shut down the Control Center using the icon in the system tray, but there are two or three AVG listsings when I go Ctrl+Alt+Delete. I don't want to get rid of AVG; I'd just like to put it on the sideline while I try Avast (and vice versa).

 

avast

avast i like it i use it and get it nuff said.