Last time I did that it froze whilst turning off.
I haven't dared turn it off since.
( Bats, Wed 27 Aug 2008, 9:23, archived)

If it's freezing just turning it off and on, it might indicate that it is just knacked
Have you go the HP software installed?
( Theoban What of it, Wed 27 Aug 2008, 9:24, archived)