Retrieving backup when computer is wiped

I have backup sets for several computers in Norton's backup site.  I am running out of room and want to download an entire set before deleting it. Unfortunately the computer that created it was wiped and given a new identity by the factory. So the norton progam won't show me that backup set when I use my backup drive to try and retrieve it. When I go to the web I see the set but it wants me to download them one file at a time - all 35 gigs or so. That won't work for me.

How can I access those files so that I can retrieve them all as one set?

There must be an answer since backups are to protect data for just this sort of event.

Thanks!

Mark