Okay, that didn't work.
I reformatted the USB drive, I added a new job with the 6 folders to back-up. I checked full back-up box, set it to differential back-up.
All it did is copy one folder, and it is the one folder that it always backs up when I do this. The only way I get a full back-up is to set the back-up to full, not differential.
So, can anyone help. If it means anything, the one folder that it does back-up was added after the first time I tried a back-up so in my mind it seems that have it ingrained that is the differential and only copies that, however that was weeks ago. Please please help!