I changed a few settings in the bios., I know I should have done one at a time, but!
The system became unresponsive after a while. This traced to System>Preferences>Power Management: "Put Computer to sleep when inactive for: "10 Minutes", but it would not come back.
Unless it was set for "never" so it never sleeps.
Then I found the hibernate function does not work.
Do I need to install hibernate + tuxonice?
Here are the power settings in the bios:
ACPI function [Enabled]
ACPI Suspend Type [ST(POS)]
Soft-Off by Power Button [Instant-Off]
WOL(PME#) From Soft-Off [Disabled]
Intruder# Detection [Disabled]
Cool N'Quiet [Enabled]
Power On By PS/2 Mouse [Disabled]
Power On By PS/2 Keyboard [Disabled]
PWRON After-Fail [Off]
Power-On by Alarm [Disabled]
Power Managerment [User Define]
Video Off Method [V/H SYNC +Blank]
Hdd Power Down [Disabled]
Hdd Down In Suspend [Enabled]