UND standards for undefinted symbols as far as I can tell and it's one of two causes. Either it was something nice like a JPG and the part of the file that identified it as such was overwritten and/or not recovered OR your recovery software couldn't determine the filetype so it just stuck UND there as a placeholder. Either way, the file is probably shredded as hell. But in you have any idea what type of file it's supposed to be based on the filename, try opening it with that program. If it's something complicated like a PDF file, it's not gonna open. If it's a JPG or movie format, programs will attempt to play/view the "good" part of the data. I'd suggest attempting to open them with Windows Picture and Fax Viewer (the default image viewer in XP) or VLC media player, which can play basically any format audio or video file. VLC isn't built into windows but it's a free download and totally spyware free and stuff.