Whee...
This has been happening for a wee while now (basically ever since I
moved to 2.5.x I think but I don't use shutdown -r now often).
Essentially, when I do it, the laptop goes through the motions, the
kernel (I assume) says 'Resetting System...' (or Restarting - not too
sure) and then turns itself off. When I do ctrl-alt-del it reboots just
fine. I'm using ACPI if that's of any help.
--
All people are equal,
But some are more equal then others.
- George W. Bush Jr, President of the United States
September 21, 2002 (Abridged version of security speech)