Where is my Catalog?

PSE 8. Windows 7.

Some time ago I put all my photos on an external HD. They are at My Pictures EXT on that HD. Organizer under Catalog Manager says Catalogs Accessible by All Users are found at My EXT Catalog [Current] but doesn't say where that folder is. There is nothing with that name on the external HD where the photos are. There is only a folder called My Catalog Backup that I made recently. So where is My EXT Catalog [Current]? Is the backup folder the one that's used?

I am able to see the thumbnails for my photos in Organizer so the catalog must be somewhere?

What shall I do?

Eva