doublekiller is pretty good. double killer pro is faster
visipics is great but slow.

most of the duplicate file programs i've used get choked up when dealing with huge amounts of files (e.g. 40gb folder with millions of images).

most (all?) do not have the ability to save a database of hashes. so you can save time in the future.

many have options to select multiple dup files, but the filters can be confusing or not as specific as you need them to be.

i guess what i'm saying is... we need a 'comparison of duplicate file finders'

filters:
filter results by directory
filter results by size/type/name/lackofname (select numberd filenames only)
filter results by drive/folder

scan:
selective hashing (scan first and last 10 bytes of a file)
multithreaded
same size sorting for faster scan

interface:
side by side compare
delete to recycle bin
move dupes to selected folder
good status/progress indicators

i installed urlsnooper on a new pc and it was having problems detecting the network adapter.

i have a few NIC's installed , and thought that maybe that was causing the problem.

disabling the non-connected LAN's allowed urlsnooper to find the (only remaining) network and work properly.

hope this helps!

if there is a torrent of the original file, you could join the torrent and select your bad hash file as a partial file. then the torrent program would scan your file and redownload the bad chunks...  (and since you have three files, you would load up all of them , perhapse in three different clients or pc's? ,and then join the torrent, it might be that you have a complete file out of your three downloads)

this also would work on the edonkey p2p network , i think...

also there is a freeware program called 'zidrav'. so if you know of someone else that downloaded the file, you both run zidrav and you send him the checksum and he sends you a 'patch' :)

ZIDRAV is a file corruption detection and repair program. It's designed to provide a way to fix file damage without having to redownload the entire (potentially large) file over a (potentially slow) connection.

http://sourceforge.net/projects/zidrav

-- i bet this program could be advanced with a nice gui and perhapse some internet support/automation, if any programmers want to take a crack at it--


but yeah, interesting problem and good luck!