They system wont Power down the mother board

["J.S.Sahambi" <jsahambi@iitg.ernet.in>]

I have a PIV on ASUS mother borad. When I shutdown the machine in 
windows, it power downs the mother board. But if I shutdown the system 
in Debian, the system does the usuall work, prints out:

...
.....
Power down.


and then stays there only. I have to manually press the power switch to 
power down the whole system. I used the  append=apm on" in the lilo.conf 
but of no avail. I am using 2.4.29 (testing). Can any body let me know 
what i have to do so that the motherboard power is shut down after a 
normal shutdown.
Thanks
J S Sahambi