How can I find hard links on Windows?

All files are hard links, with link counts of at least 1.

This is why the files look the same. They are the same. What you seem to be looking for are files where there are more than one link to the file. There's very little that distinguishes a file with a link count greater than one from a file with a link count of one … except the link count (and some odd behaviour with respect to attributes and date stamps).

And that is dead easy to check with the find command that is in Microsoft's SFUA utility toolkit, that runs in the Subsystem for Unix-based Applications:

find . -links +1

On Windows 7, use command:

fsutil hardlink list MyFileName.txt

It lists all hardlinks to file with name MyFileName.txt.

Unfortunately, there is no way for the OS to find all your hardlinks without looking at each file.

For Explorer, you can download the very handy Link Shell Extension, which overlays files with hardlinks with a red shortcut-like arrow.

It also makes it rather effortless to create hardlinks, symlinks and junctions through Explorer's context menu.

Bonus chatter:

Technically, all files are hardlinks. Thus, you are really looking for files with more than one hardlink.