I found this information. Enjoy
My Windows XP took up to 30-45 seconds to shut down. I found this tweak and WOW!!!
Please back up your registry before making any changes.
Go to Start --> Run and type Regedit Navigate to :
HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Control
Click on the "Control" Folder In the right window you will see this key WaitToKillServiceTimeout
Double click that key and set it to a value lower than 2000 -I set mine to 100 then Rebooted.
Take Care..........
