[Gutsy] Can't Power Down

[NoOp]

Did an upgrade on an old HP XE744 desktop from Feisty to Gutsy & all was
working pretty well. However on this particular machine I'd also
previously had LAMP installed, various flavours of Kubuntu etc., all
since removed. It seems that removal of the LAMP & K's didn't quite
clean everything out so I decided to do a fresh install.

Install went well, got things configured as I wanted them & then I
powered down... almost -- powering down no longer works. Hard drive
shuts down but fan & power LED stays on, and the final Ubuntu splash
remains on the screen. Only pushing the power button on the desktop
completes the process. Reminds me of the old Windows "It is now safe to
turn off your computer".
Kernel is Ubuntu 7.10, kernel 2.6.22-14-generic.

Anyone have a similar problem or fix? I've been trying all the noacpi,
acpi=force, noapm, etc., etc., but still can't figure out the problem.
I'm thinking of loading Ubuntu 7.10, kernel 2.6.22-14-386 as that was
the working one on the upgrade prior to the fresh reinstall.