Backup Windows Files Using Robocopy
Robocopy is a useful program from Microsoft that can be used to do file backups efficiently. I use it to copy files from my local hard drive to an external hard drive. It basically keeps the external drive synchronized to the local drive by (1) copying new and newer files to the external drive and (2) delete files from the external drive that have been removed on the local drive.
You can get Robocopy by downloading the Windows Server 2003 Resource Kit Tools from Microsoft.
I use this type of backup to backup my entire My Documents and Settings on my local drive and an external USB drive. If the external drive is always on, this script could be automated to run at pre-scheduled times.
Note: Make sure your test your scripts thoroughly on dummy data before using it on your real data since you could lose all your data (if, for example, you switch the source and destination paths).