WD Smartware not backing up?

Since I’ve been backing up my laptop (Gateway W350A, Windows Vista 32 bit) I’ve been, or at least I think I’ve been letting Smartware do a complete backup of all content on my computer on my Passport Essential 465GB, Firmware version 2.003.  As I fill up my local drive, I’ll do a backup and then delete unnecessary files to create more room.

It’s been a while since I’ve done a backup and there are about 4.5 GB to move so that my local drive is not full.  In Smartware I can see that it recognizes this data to be backed up as yellow in the graphic representation of my content, but I see no changes in the size of backed up data or in the number of files backed up on the external drive; even after about 5 hrs of letting it work.

What is wrong and how do i know if my data is bing backed up?