I ran into this issue and asked the owner to demo the problem. They reached down and pressed the "reboot" button. This helped find the cause in a flash. A short lesson later about properly logging out and the share stuck the next time.
I am sharing drive F: in win2000. When I reboot the drive is no longer shared. How do I save the setting?
I save it by right clicking on the drive in explorer, clicking "Share this Folder".
Drive C is also shared, but it maintains that share upon reboot.