I've noticed that when the exit windows and start windows sound is enabled ... the system takes a lot of time to boot or shutdown. You go to Control Panel and click on Sounds and Audio Devices. There you go to the Sounds tab (2nd one on top) and look at the list labled Program Events then find & click on Exit Windows. Right below the "Program Events" list there's a drop-down list labled Sounds, open it and all the way up you'll see (None). Choose that and then Apply and you're done. Do the same for Start Windows.