Success! As I was contemplating my Lightroom situation I got to thnking that maybe the thumb drives were the problem. Sure enough, I pulled out a spare external hard drive, hooked it up to the Lenovo and VOILA the thing did what it is supposed to do. The ADD button was available. I could choose a file on the external drive and it would let me add it to the catalog. That is what I wanted. Apparently thumb drives and SD cards can't be directly used for a Lightroom photo file and catalog. There is a work around that I intend to explore eventually. I like the idea of taking thumb drives along rather than an external hard drive. Of course there is more experimenting to be done, but there is no imperative to do so because we don't need the Lenovo in the near future.