Continuous Backup Software Advice

Hi,

I installed new win7 version (from home to ultimate). Before new installation I had My Book connected and automatic backup on.

C and D partition were backed up on the My Book. D partition stayed the same (on computer), with only minor changes in new files. C partition is system, so it's completely changed...and it's not really important to be backed up because I don't keep any docs there.

After the new win installation, I installed WD again. In My Book folders I can see all previously backed up files. But when WD finished with analyzing and I clicked Start Backup (for D partition) I expected it to recognize all previously backed up files and only update the new ones. But it actually created a new folder and started a backup of 600GB...which are already there, only in different folder...

I asked on WD forum if there is a way to "direct" WD to previous folders locations, so it can recognize them and just update new files? Otherwise, My Book is gonna be full of duplicates... but I didn't really get an answer I was looking for.

To avoid these issues with future Win installations, I thought that a portable app that can do continuous backup would be a win for me for the future...

Any ideas, advice...?

Thanks!

Lik