Quick question about backing up
 

I've been using SuperDuper for many years now (and love it). A few weeks ago our hard drive started acting up, so we switched over to using the backup as the main system. I just found out that the hard drive isn't the problem but the enclosure, so I put the original hard drive in a new enclosure and now it seems to be OK. I would like to keep the original hard drive as the main system, but there is now two weeks worth of new stuff on the backup. So here's my question;

Original hard drive has 3 files on it; A, B, and C

We do a backup and our backup drive also has A, B, and C

Then we switch over and start using the backup for a few weeks so now it has files A, B, c, and X, Y Z.

If we use the backup as the source and copy onto the original drive, will it copy over just files X, Y, and X?

The reason why I ask is that there is a program on our backup that seems to be corrupted and does not work. However the copy on the original drive does work.

I don't want hurt the good copy of the program (on the original drive) by over writing it with the corrupted version. Hope that makes sense :p

Only changes will be copied. So, A, B will be the same, C will be overwritten by c, and X Y Z will be added.

I would think smart-update would now give you the corrupted file/program on your main drive too - I'd work at sorting out the corrupted file/program before I did a backup if I were you.... maybe copy across from main drive to backup (or reinstall it from installer) before then using SuperDuper! to sort out other changes....