Losing Default Shares on Startup

I have an NT40 server (sp5) that when I bring it down loses its default shares. When I bring it back up I need to go to each of the drives and share it with it’s C$,D$,K$, etc. share. As soon as I do it works fine until the next time I bring it down. It is mostly a nuisance, since when the default shares go away the backup routine doesn’t work proerly. I don’t want to forget to do it sometime and then not have a needed backup. THanks for help