NoClone is a freeware that lets you find duplicate files located on your Windows PC. This freeware allows you to safely find and remove true duplicate files, photos, MP3s as well as Outlook email messages.
It uses real-time byte-to-byte comparison to detect duplicate files regardless of their file names. You can limit the search to specific file types (images, programs etc.) as well as by size, date and location.
After the freeware completes searching your PC for duplicate files, it will present you with a list of all duplicate files found and you can check the ones that you want to delete or move to a different folder.
In addition to finding true duplicates, the program also offers support for fuzzy search matches which enables you to find files that may not be exact duplicates but appear to be very similar.
Other features include side-by-side image preview, compare the content of folders and compare file changes against USB drives and other portable drives.
The free edition restricts itself to 300,000 files in a single session.
Looking for more? Check out this post on duplicate files finder freeware for Windows.