Re-enabling and continuing WD Automatic Backup after OS reinstall

Hi!I own a WD My Passport 1 TB External Drive that came with WD SmartWare version 1.6.4.

I had set it up to automatically backup Drive D on my laptop where all my data resides.Windows 7 OS is setup on Drive C but I had an OS issue that forced me to reinstall the OS afresh.This means that I have installed SmartWare afresh also.

Since Smartware had already backed up my entire Drive D in the old OS,I want the SmartWare to simply append new files saved on Drive D onto the External Drive with the new OS installed instead of starting the entire backup of Drive D afresh.
How can I acheve this?I hope my request has been understood.

Hello, 

If the file structure, the OS, the user accounts, and the computer registry stills the same, it should be able to recognize the previews backup.  If any of the previews information is different, you might need to create a new backup.