Hello I have this exact same problem and a quick google search shows that many other people do also. The box is permanently open and I can't get rid of it by restarting my computer. It blocks off the whole bottom right of my screen.
"Please wait while AVG applies your security settings.. open any browser until the process i.". the rest is blocked off. Reading other responses even uninstalling AVG does not remove the box. Does anyone have any advice on how to?