Hard drive backup?

Hello
I need to backup one of my ibmthinkcenter system by nero 6. I have backed many pcs, but, this time we got from our supplier the systems, when I go to the backup hdd option in nero it shows the whole partation, instate of C: disk. when I try to backup it take a minute to backup and the file size is lese then 2 MB which suppose to be more then 2.5 GB. I think the C disk is hiden or me be something else. Could someone help me out please?

Regards