Help on Windows 2000 server security

I hve a Windows 2000 server installed on which I hve my Proxy Server Installed. I want to set a security that only the administrator can see the IP of that PC and he can only access the drive on which the proxy server is installed. The name of the proxy server is Winroute Firewall 5.0
I also wanted to know that if I want to a hve a different subnet mask for that PC how can that be done.