trouble finding files after backup to external hard drive

I have a Dell Latitude D830 and have used Vista's Back Up
and Restore feature several times to backup my computer to my 500G LaCie external hard drive. (I have been on the computer when it has
stated it is starting back up and that back up was successfully completed.
I assumed everything was fine until today when I was showing my mom my
external drive and noticed that none of the back up files were there...or at
least I didn't see them. The only files on the drive were the ones I had
manually put on there from my old computer. I then ran a manual back up
using Vista and again it said back up successfully completed. I then looked
at the external drive and again no new files. The odd thing is the back up
and restore program shows all the dates it has backed up and also allows me
to restore files from back up. To check this I deleted a file I didn't
really need off of my hard drive and then went to the restore program and
found the file and restored it. Problem is the program doesn't say where it
is getting the file from. What is going on? Are back up files some type of
hidden file that I can't see unless I'm using the backup and restore program
in vista? I also tried a manual backup through LaCie's built in program and though now I see a new folder which according to the properties has 160G has nothing inside when I view it through the file explorer. Any help would be greatly appreciated!