ok, well, I finally figured out the answer.
Thanks to grimx133 and bluesrocker (and anyone else that brought it up.) I didn't think about the command prompt at first. So, here's the issue:
I
thought I had Vista on this drive and then put it back to XP...but as it turns out, it was still a Vista drive. Vista does
not use the "Documents and Settings" folder anymore as XP did. Instead it uses it as a <JUNCTION> to the new "Users" folder.
I noticed when I went to the command prompt and did a 'dir' that the folder was hidden.
When I right-clicked it in Explorer and looked at the properties of the folder, you can NOT uncheck the hidden attribute -- however, you
can unhide it using the "attrib" command in a command window.
When I did that, it magically showed up and showed <JUNCTION> rather than <DIR> like all the other ones do.

That's when I got the reminder that Vista uses that folder as a pointer, or as a "junction" to Vista's new "Users" folder.
So, sorry to lead everyone on a wild goose chase, but at least we can all chalk it up to experience -- one I won't forget (again.)
Thanks for everyone's advice!