I have the same problem. The point is, that with breezy everything was fine. The problem started with dapper. This means, I think, that it is not a problem of outdated bios. It is a problem with kernel/acpi...
-- [Dapper] Shut Down won't power off https://launchpad.net/bugs/42160 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
