unreadable Data after XP reinstall

I installed windows XP and had problems so before reinstalling,I copied data to a CDR. All seemed fine. I then reinstalled windows & reformatted drive. After attempting to use the old authorization key, it said it was invalid and I had to call microsoft to get a new key. Under the new XP install, I can see all the files with correct names on the CDr, but the data looks encrypted. All the files on the CDR are present with data unrecognizable.
I used UDF packet writer from explorer to write my files to cd.
Does XP encrypt the data? If so, how can I translate the data?