Backup Outlook 2010 on Windows 8.1

My wish is to create an incremental backup of an open Outlook pst file.
In a recent GeekBuddy session I was informed this was not posssible.

My next option is to take a backup of a closed Outlook pst file once every night.

How can I set up a command that will start the machine, logon, and run the backup and then logout/close the machine.

If I missunderstood the GeekBuddy session please let me know.

regards Anders K