This just happened. Really.
First, some background: the family laptop runs Windows Vista. It came preinstalled. Nothing we can do. As we all know, Vista is a lesson unto itself on inefficient code. Even with the laptop's 2GHz processor, it takes 20 minutes to boot, and another 20 to login. Shutdown isn't as bad; it usually takes 5-10 minutes.
Tonight was not usually.
Tonight, the laptop took so long to shut down it actually triggered the screensaver. I stopped the screensaver to reveal--the login screen!