We run a small network of users from a central SBS 2008 server that handles group policy & AD. Most of our users operate under a policy that propts them for a password change every 6 months as a security measure, with a few administrator accounts & terminal machines not using the policy for the sake of ease as they are needed all the time. Recently all machines regardless of policy have started asking for a password change out of schedule. Some PCs run Windows 7 & some XP, though the password prompts don't seem to discriminate between OS. What could this be down to?