Originally Posted by Jack Malmostoso
That said, the kernel argument that does the trick is "acpi=force". You have to edit /boot/grub/menu.lst so that your "kernel" lines read something like this:
kernel /boot/vmlinuz-2.6.XX-XXXX acpi=force ro root=LABEL=/ rhgb quiet
I had the same problem. When I used the Shutdown from the menu, I got to a System Halted message. Put in acpi=off in the kernal argument line, and now it works like a champ. Thanks Jack!