Been dealing with Error event ID 454 in our event logs on our Windows XP SP2 machines and then they get stuck on saving settings when you try to log them off for quite some time. The only way to get rid of it is to shut the things down by hand. If Windows update doesn't work for you this fix will help also.
I found this obscure posting out on the web that suggested reregistering a dll on the system. I have to admit I was skeptical but it appears to have resolved the issue. So here are the steps.
Go to a command prompt and type
That is it. Workstations should log off much quicker now. Apparantly this dll gets corrupted or unregistered for some reason. If you add a /s the box won't pop up saying it is registered so you can do this on a script. We pushed it out via Altiris today and XP machines seem to be much happier.
Microsoft MVP - Terminal Services
Terminal Services Downloads: http://www.thinhelp.com