Recovery from previous backup

I posted a question on Norton Communities a couple of days ago.  The problem that I had has now been resolved however the question of how to recover files from an earlier backup is still outstanding.

The issue that I faced was that one particular folder had disappeared and did not appear in my latest Norton backup.  My external backup drive contained one additional backup to the latest one so I wanted to see if the missing folder could be recovered from that however Norton recovery would only point to the last backup not the previous.

I have managed to recover the missing folder by another means however the issue of "how do I recover from a previous backup" is still a question that I would appreciate an answer.