We have about 60 PCs in our high school, running Win XP Pro with a win 2003 Server. Virtually all of the computers' clock times are 10 minutes slow. If they're changed, they revert back almost immediately. On most PCs this isn't much of an issue, but tardy students are getting away with being 10 minutes late (IDs are scanned) and this has become a big problem for me. Any suggestions?