Here's another one, and I don't remember whether I asked about this one
before or not.

In 2007.0 and 2007.1, when I hit shutdown, the machine actually powered
off. In 2008.0 and 2009.0, I see it call the appropriate acpi routine,
and I hear the disks spin down, but the power does not actually switch off.

The board is an Asus A7S333 with an Athlon XP processor, currently
running the 2.6.27-desktop-0.rc8.2mnb kernel if that makes any odds.

Has something changed in the kernels to stop this working as it should?
And if someone can show me how to diagnose the problem I'd be grateful.