HP 742n - Pavilion - 512 MB RAM White Paper page 6

The Power Button and Unexpected
Wakeup
The operating systems Windows 2000 and Windows
98 SE both enable software-configuration of the PC's
power-on button. Depending on the chosen
configuration, the push-switch may not behave like a
hard-wired on/off switch, and the user should no longer
expect it simply to turn off the PC's power supply. The
PC could instead go into a power saving mode such as
Hibernate, where it is still under tension.
Furthermore the PC can automatically power on, for
example for scheduled maintenance or remote
management. Users should realize that the PC can "turn
itself on" and that this is normal behavior.
PCs with a network card supporting RWU (Remote
Wake Up) can be woken up by the network in this way.
both
Most non-ACPI PC models equipped with a network
card that supports Remote Wake Up or RPO (Remote
Power On) can also be woken up or restarted by the
network.
It may be difficult to discover if the PC is in a low power
state or is turned off (electrically isolated from the power
source).
Considering these points, before any maintenance
action you should wake the PC and carry out a shut
down (S5) to ensure it is correctly powered off. Always
remove the PC power cable from the socket before any
maintenance actions. This ensures that the PC is 'off' and
disconnected from the power source. Please read current
HP documentation on "Servicing the PC" before starting
an intervention.