Depending on how much the HD has been used since he installed Win 7 would determine how successful a file recovery tool would be--the more usage since it was installed the less likely you'd be able to recover the files, they actually suggest you not use the HD at all after you discover you've lost the files.
As for a file recovery tool, download TestDisk (its free)
Comes with a tool called PhotoRec which you may be able to use in order to recover the files, although it will not retain the name of the files (will be a letter and a series of numbers) but since its in .adf format you could in theory sort by file time and find them that way.