I don't see how re-installing could actually wipe the content (or why it would do it in some cases, but not others).   If it had been deleted, you ought to find something in the re-cycle bin, although it would be only a small subset of the total.   Have a good look at the directory structure, in case you have a complete Geometries folder, for instance, inside your new Geometries folder.

Poser can also lose pointers to external libraries, but that doesn't erase the contents;  it is just a question of setting the pointers up again.