This is the third time I've seen this when working on site for a customer, so I know it's possible, I'm just wondering how.
It seems that the Local Administrator account has it's password changed everyday, even if not connected to the domain controller at the time, automatically. The workstations are XP, Vista or 7. I know they weren't connected to the domain controller when this automatic update happens, because the latest client had the NIC fail before the next password change. How can I automatically change the Administrator password on a schedule, and how can I find out the formula for what the next password is given x day of y month?