XP Home SP2 hangs during restart, but not reboot

It seems whenever I use the 'Restart' option to reboot, my desktop system
hangs up during the reboot, always during the screen with the WindowsXP
splash screen and the little blue dots that scroll from left to right.

However, when I then reboot by pushing the reboot pencil switch on the front
of the desktop, everything comes up fine, even when I select 'Start Windows
Normally', (instead of 'Last good configuration').

Any ideas what's going on here? I thought I might have a bad sector that's
only accessed by some system driver during reboot, but then the Start
Normally shouldn't work.

If it is a bad sector, is there some utility I can run to check for that?
(My disk is NTFS formatted).

Any feedback is appreciated.

--
Gregg C.