I have 50 computers on a network. All computers have same password for username (administrator). I have file sharing activated. My problem is - each time I type \\computername\c$, I am able to access the C drive without prompting for the username and password. How can this be prevented? How can I have the computer prompt for the username and password for access? Thanks

Oxymoron "All computers have same password for username (administrator)" and "How can I have the computer prompt for the username and password for access?" You have to make up your mind. Either you want all admin accounts with the same password or you want them to be different so you are challenged for a password. Don't confuse your administration with user logons which should be challenged for credentials.