Tried to do a firmware upgrade on my fiance's Reader and the upgrade took forever, quite literally. Decided to pull the plug and I ended up with a brick.

I was pretty embarrassed and upset about this considering my upgrade went without a hitch. In fact, this happened on Monday and it took me until now to get over it. The Reader is still under Sony's replacement program so she'll get a refurb to take its place. The problem is that it was engraved and that'll be gone. Such is life with firmware upgrades I guess.
So what needs to happen with the registration in order for the new unit to be able to read the books she purchased? Does she need to de-permission the older Reader or does the software go by computer and not Reader?
Thanks in advance.
Nathan