ACPI problem: Machine Cannot poweroff.

Tue Aug 5 17:52:38 UTC 2008

My machine is HP Compaq Presario V3805。 OS is FreeBSD 7.0-Release.
(uname: FreeBSD blueroad.ux 7.0-RELEASE FreeBSD 7.0-RELEASE #0: Mon
Jun  2 22:33:43 UTC 2008     root@:/usr/obj/usr/src/sys/BLUEROAD
i386)
When power wire remove and connect again,  the machine cannot poweroff
normally. I must press the power button to force power off.
Also, keypress on the console become slow down. Does anyone have the
same problem? How to solution this condition.