Seems that if you have an XP professional system and add a drive, that drive gets formatted by default as a 'dynamic' drive.

If you then reformat the boot disk and install XP Home, you can no longer read that additional drive. XP Home doesn't recognize 'dynamic' drives, only XP Professional does.

So, when I copied all of the email, favorites, documents, jpgs, mp3s, and other stuff the user didn't want to use over to the 75gb additional drive for safety and so I could put things back once the boot disk was sterilized and reinstalled with a fresh OS, I was unable to use that data with the new XP Home system. Lovely.

Solution?

Added a 40gb drive of my own, formatted as fat32 under XP Home.

Booted to Knoppix 3.4, copied all of the data from the 'dynamic' 75gb drive to the normal fat32 20gb drive. (there was only about 12gb of data in all)

Booted back to windows, converted the unreadable 'dynamic' drive to the XP Home-friendly 'Basic' drive type. (This ERASES the disk, so be warned.)

Copied all of the data from the 20gb fat32 drive over to the freshly formatted 75gb ntfs partition.

Rebooted again, to remove the 20gb drive and put the lid back on.

Took about 4 hours.