You can, in fact, remove those shares.
You must first be logged in as administrator >
Use explorer and right-click on the C drive. (or whatever drive/folder is being shared as C$ and ADMIN$) Go to Sharing and go can remove the C$ share.
When you install Windows 2000 Pro and choose "Typical Network Settings", it will install Client for Microsoft Networks, TCP/IP and File and Print Sharing as a default.
During the installation, you can change this so that it doesn't install File and Print Sharing from the beginning.....when you are asked, Choose "Custom Network Settings/Configuration"