My GUI freezes, along with the keyboard and mouse, rescue always has been 
via reset button. I am uncertain direction to take to sort this out.

At least once when this occured, I could remotely access the box. Also 
during this same event, a CPU/memory hungry program I had begun on a 
virtual console completed successfully with complete and correct looking 
output. This seems important and suggest (to me) a problem with Desktop 
management (gnome-session).

On the other hand, log files for today (2/3/15) report 52 CPU stalls 
("self-detected stall...") in about 8 hours. Web discussions suggests this 
is related to kernel handling of the tsc register. Web discussion (and the 
tsc kernel route comments) also suggests that problems are solved (or at 
least managed).

Thanks,
Mark Hansel