I had to replace my hard drive and reinstall LR Classic CC. None of my 5000+ photos are in the library, or any of the presets I've purchased. How do I locate all my photos?
If you didn't make backups of both the LR Catalog file and all your image files on to an External drive or other computer then I'm sorry to say this but all your images and work on them are gone.
If you do have backups of both then you need to restore the backup of the images into there original folders and then open the backup of the LR catalog file.