Acer 500 User Manual page 59

There are two necessary conditions for the computer to
enter Hibernation mode:
The Hibernation file created by Sleep Manager must be
present and valid. See "Sleep Manager" on page 67.
Heuristic Power Management Mode must be set to
[ENABLED].
In this situation, there are four ways to enter Hibernation
mode:
Pressing the Hibernation hot key Fn-F4
If the waiting time determined by the computer's power
management system elapses without any system activity
If a battery low condition occurs and the Battery Low
Suspend parameter in Setup is set to [ENABLED].
Invoked by the operating system power saving modes
Note: If the computer beeps but does not enter
Hibernation mode after pressing the Hibernation hot key,
it means the operating system will not allow the computer
to enter the power-saving mode.
To exit Hibernation mode, press the power switch. The
computer also resumes from Hibernation mode if the
resume timer is set and matched.
Warning: Do not change any devices (such as add
memory) when the computer is in Hibernation mode.
Chapter 2 Operating on Battery Power
Power Management
39