10.4.9 Upgrade Issue - Shut Down Freeze

I upgraded my 12" PowerBook this weekend to 10.4.9. Ever since then, the laptop seems to freeze during shut down. I get to where only the desktop image is showing (desktop icons, the Dock, and menu bar are no longer showing), then nothing. It never shuts down. I've left it for at least an hour and it will still be stuck there. Any help would be greatly appreciated. Thanks!

PowerBook 12" (Aluminum) Mac OS X (10.4.9)