My HP Pavilion (8560c) has started freezing on most
shutdowns. There's a symptom that tells you it will do
this (as opposed to shutting down normally): the little
light next to the (built-in) CD-ROM drive flashes on and
off, even though there's no CD in it and it's not being
used. When this happens, you can't open the CD-ROM drive,
or access "My Computer" on the desktop, and you know that
it will freeze when you shut it down. (When that light
isn't blinking, it will shut down fine. But getting to
that state is a matter of luck.)

Any suggestions?

Thanks!