Admin and default drive shares removed.

I have inherited a Network that is running WinNt 4 Workstation and Server. The previous Admin removed the default Admin$ and c$, D$ shares on the Workstations. Now I am finding that I need these back in place so that I can remotely install Norton Anti-Virus Corporate Edition.
I can go to the command line of each Workstation and enable the shares; however, upon reboot the shares are no longer there.
It seems as if there is some sort of Registry hack that was performed to remove the shares.1.) How can these shares be renabled and retained when the system is rebooted?

2.) How can security be retained with these reinstated?