@gollum,
I would not worry about this if it is a one time hang up and just unplug it and see if everything reboot correctly afterward.
Some program just got hung up and would not allowed a normal shut down.
You might wish to go to the control panel and under adm. tools go to event viewer system tab and see if there are any interesting errors or warning messages.
Oh this last update is large and work the hell out of your hard drive installing all 12 of the updates
My little netbook does not have great hard drive cooling and a temp. monitoring program warned me that I was ten degrees over the maximum safe temperate for the drive so I needed to run and set up a fan on the computer!
Not a normal 2 tues update at all.