|Squall ... we learn every day!|
What you should have done (according to me), is this :
Since you only wanted to have data from "My Documents", you should have made a copy of that data, onto another media:
Another HD (a physical one, an USB harddrive), a USB stick, a DVD, BluRay, CD, whatever ...
If you have the luxury, copy the COMPLETE drive (partition) to that media.
Then, install XP64 on the C: drive, and unless you have a need for it, forget partitions.
Then use the data you've stored before, to restore to the only OS you have at that point, or use it in any way you like.