uhm this is a "non answer" i sadly have not done this in vista, but usually the C:\documents and settings\username should be there.
might look like this in Linux

/sda/documents and settings/username
you could try searching for a known filename, open the file manager (konqueror) and choose tools, there you have the file search tools.

what do you want to use it for? you can only read from there safely, writing is not safe in my opinion, use a USB memorystick or similar for that.