Do you see the "Closing Network Connections" message? Does it take a long time on that message, or is it after that?
If its on that message, check all network connections are running properly.
es not close (in the background), it keeps trying until at some point it give the "not responding" message, which you might not see because its in the background.
It doesnt come up with any messages or anything, just sits there for about 2 minutes and then shuts down.
Ive also set settings in the registry to end non-responding tasks. ("AutoEndTasks 1"). Also "HungApptimeout 5000", which means it should wait 5 secs for it to close before ending it automatically.
Simon im thinking that setting might be applicable to you. You mentioned earlier that it takes 40 secs to shut down, and the default value of HungAppTimeOut is 40000 (or 40secs). You could try lowering it to say 5000 and see if it shuts down any quicker.
Boss
EDIT :Also WaitToKillTimeout is set to 4000 on mine. I think ive got all that right, you might want to refer to that guide above, as ive probably got bits slightly wrong.