Hard links are just pointers to the file. You can remove any or all of them independently of each other and the running program. In fact, IIRC there's a semi-common pattern where a program will deliberately create a file, open it, and then unlink it, which leaves it usable but anonymous and in a state that will always be garbage-collected when the program exits.

On Windows you can't remove a file while a program is using it, that's the topic of the post. To me that implies that Windows can't keep a file around without having a hardlink to it. But what happens when there is more than one hardlink? Hence my question.