It's hidden here:
"C:\Users\XXXXXX\AppData\Local\Microsoft\Windows\Temporary Internet
Files\Virtualized\C\Users\XXXXXX\Documents\Downloads"
Replace XXXXXX with your logon name, C with whatever the Vista boot drive
is.
The virtualized folders are deeply hidden and don't normally show up even
when files and folders are unhidden in the view options. You could enable
the Administrator account, unhide system files and folders and then find
your file using search. I did that once but I also found it using an
explorer type program that doesn't obey the hidden flags. In this case I
used "Folders Report" from NirSoft.net to locate the Virtualized folders,
confirmed that my files were in there and then created a shortcut to that
folder in case I ever needed to access it again.