Every day at approximately 4PM several XP computers slow down to the point that applications hang. If the user restarts their computer then everything returns to normal.
There are no errors logged by the 2003 server.
The computers log events 1053, 1054 Userenv, and event ID 15 Autoenrollment. The users complain that it takes a while to log in, but once logged in the system works fine until 4PM.
All of the computers are Windows XP Pro.