2GB iPod Nano's backlight keeps flashing off and on with the apple logo!

My iPod nano will not turn on or off. It will not
mount on either my powerbook or PC, and no buttons
will work. I've tried to reset the ipod by holding
down the menu and select buttons while toggling the
hold button off and on, but to no avail. I've also
tried to restore it to its factory settings, but
since my computers don't recognize that the nano is
connected, it will not work. I've considered the
possibility that it is the connection, and I've tried
connecting it to multiple USB 2.0 and 1.0 ports and
used an old and a brand new iPod USB cable--still
didn't work. Meanwhile, the backlight keeps flashing
on and off the screen showing the apple logo. I've
tried to drain the battery power and then reconnect
to see if it will work. But then I plugged the cable
into my iPod and Powerbook or PC and the backlight
kept flashing. However, it did begin to charge which
is some indication that the connection is fine. I've
run out of things to try and I'm desperately seeking
help because my nano worked fine just last night.
Please help 😟

PowerBook
G4 15'' Mac OS X (10.4.3)