Our main-con manager is looking for a "punch card" type of attendance-logging application. We need to take attendance every day, and the most "automatic" method is simply to track when people unlock their Windows desktop screen (not logon, because many simply leave the computer on indefinitely), and report to a remote location/repository, where the administrator will be able to observe which users unlocked their screens each day.

Has anybody come across such an application suite? It likely has to be a Windows service so that it operates regardless of who is logged into the system.