The turnoff can be due to overheating or power problems. Or the event log might have a clue (Control panel->Admin tools->Event log->System).   What do you mean by "jumps back to the Continuum menu"? That would be the one with the zone list, but you say you hear the sounds? Do you mean the chat window? If yes, sounds like some program is stealing focus. Try closing programs. Sometimes programs get stuck minimized for me too, but when I start the program again, it works for me.