Vista - Backup Utilities not working

I've been backing up my files regularly using Drive Manager (the software provided with the Seagate), thinking I had everything covered until yesterday. I decided to check the files, so I dug through my external drive (A Seagate 750 GB External HD, no Firewire) into my backups. Lo and behold, I only found the .exe's for some install files from my download folder, and a couple of zips. All these were in Users/Public/Public Downloads.

I can't seem to find anything from my /Users/(my acc) folder. No music, no .docs, no .ppts... Nothing. Only the top two or three levels of folder structure. I'm stuck with manually copying things over that I would rather have the automated program do.

This has happened to me before with Vista's built in back up utility also.

Err... Anybody? I'd like an answer please.