one comment to rickh. I agree completely with you, except the first sentence*g. secondly, it is also possible to get a functioning acpi by getting the right dsdt.aml for your pc or laptop (I forgot the link where you can get it). Also as stupid Suse user as I was able to compile a dsdt-table on my own...., so you don't need - in the most cases - to use the noapic or acpi=off boot option.

ps.: the answers you get here are only as good as the questions you got, so read again the first question and tell me what it exactly was hunting for.... I did not get it...

try "shutdown -h now" under root