In the initial days, when you try to restart or shut down a Windows
Vista-based computer, the system may take a long time to restart or to shut
down. Alternatively or Additionally, you may receive a message that resembles
Windows is configuring updates. This may occur 1-2 days after you first
start Windows Vista; or sometimes after a WindowsUpdate.
This problem occurs because the system must perform maintenance functions to
delete unnecessary files. Typically, this process will occur one or two days
after the Out Of Box Experience (OOBE) Wizard runs. When this problem occurs,
it may take as long as 10-20 minutes to shut the system down. The process
occurs only one time.
Suggested Solution : just wait for the process to finish once.
Microsoft MVP 2007 Awardee.