You should concentrate on the console. Check this well when the system is still working, and log its activity. If there is no other way, than make a movie on the console screen.
You may configure some hardware monitoring software as well.
Server hangs in the middle of the night
Re: Server hangs in the middle of the night
Server is still running. As best as I can tell, the problem has been solved. I'm closing the case on this one. Thanks.