SuperF4 kills the foreground program when you press Ctrl+Alt+F4. This is different from when you press Alt+F4, which only asks the foreground program to Exit, allowing it to decide for itself what to do.
You can also kill a process by pressing Win+F4 and then clicking the window with your mouse. You can exit this mode without killing a program by pressing escape or the right mouse button.
SuperF4 should be able to kill all kinds of processes, whether they are hung or not. Beware though, killing a program does not give it a chance to save unsaved work. If you accidentally kill explorer.exe, you can start it again by opening Task Manager (Ctrl+Shift+Esc).