I setup a number of Windows XP Pro computers, and each of them have an odd problem - I have to log off twice in order to log off at all.

For example, I log onto Windows using my network acocunt. When I am finished using the computer, I click Start, Shut Down, then select Log Off <i>username<\i> when I am finished. Nothing happens. When I do those same steps a second time, then Windows logs off and I have to press Ctrl Alt Delete again to log in.

What's causing this and how do I fix it?