Vista - Folder unaccessable after returning to XP

I had a folder with some 20 GB of data on my secondary HD, and upon my
upgrade to Vista, I could not access it.
I "Took Ownership" of it in Vista, which allowed me to use it and the files
it contained.
As I was returning to XP, I suffered corruption of my MFT and lost all
partitions on my primary HD. As this was a 2 year old XP install originally,
and all my documents were backed up, I just re-partitioned and re-installed
XP.
I now have no access to my data folder again, and cannot find a way to
change it. It tells me it is encrypted (via Properties>Advanced), but I am
unable to remove it.
I would love to have the data back, but at this point, all I want is access
to that 20 gigs of space.
Any ideas?