Atomic Clock Sync is a plain and simple time synchronization tool that connects to one of the time servers operated by the National Institute of Standards and Technology (NIST) in the United States, and synchronizes the time of your computer with the time on the server. You can choose to have the program do it automatically every day, keeping your system time accurate to the second. If you are not using XP, give it a try (XP has time sync built-in).