1. To update, use the command below (2008 and 2012 server compatible)
      change the ntp_server with your source. Check http://tf.nist.gov/tf-cgi/servers.cgi for servers
    2. Restart the time service
    3. Resync the time
    4. Verify your sync status

Commands above should be fine if your sources are working correctly and/or your connection is OK (firewall or Microsoft Forefront can be an issue also).

The commands below can help with troubleshooting

To list out peers

To list out NTP Sources: