This most likely is because zero photos from that folder have been imported into Lightroom. What happens if you select other folders?
If synchronize doesn't work, it is most likely because you have accidentally imported the photos using the COPY action (instead of the ADD option) and now Lightroom thinks the photos are in a different folder (wherever the photos were copied to).
If you click on All Photographs on the left hand side of the library module (under Catalog), and sort by file name, can you scroll up or down and find the desired photos in alphabetical order?
The problem is that no photos show up, in any folder. The whole library is blank. After closing and opening LR a few times, renaming the preference file and trying syncing (which like I said just stalls) the library finally showed up. But this is the 3rd time this has happened so I assume at some point LR will "loose" the library again. And again I'll have to spend an hour before I even get to working on photos, ugh.
I import from camera by copying from CF card to the HDD, and that also adds the photos (in the folder) to library, no? And even after it found the photos it's now showing them like an 90s dial-up connection, where it takes 10-20 sec for each photo to load in. I left it at "optimize catalog" overnight to see if that helps.