Can't see contents of all folders

I have two desktops and a laptop on a wireless network at home. I use a
large partition on one of the desktops for storing files for all three.

My only problem with this setup is that I can't see the contents of all
the storage folders from the other two computers. This problem began
about a month ago. There may have been one, but I don't remember any
event that might have caused it.

I can access most of the files from each computer, but not all of them
from either one. To add to my confusion, folder contents that are
visible to one computer can't be seen by the other.

My login accounts all have administrative privileges and all of the
folders are set for full sharing with network users. What else can I
look for that might be causing this? Thanks..