So long ago and many many times infinity(2nd grade reference there). I downloaded the Internet. Any cool app I found. Some I wish I had kept. I then found myself in a 
pickle when the downloaded software had been updated or duplicated in another folder so I had multiple copies of different versions (good or bad) and no way to keep track of any of them. So I found Dupelocater.exe. 
Drag folders from Windows Explorer into the DupeLocater.exe window and press Search.
When finished, drag the report duplicates to whatever folder you wish, or the Recycle Bin, or a viewer.
NOTE: DupeLocater.exe does NOT care about file names. Files with identical content are considered duplicates.
Also DupLocater does not seem to like Windows Vista. Go figure.
Download Links:
Drop.io
mikedopp download
Skydrive Download (Windows Live authentication required)