File sharing with Windows 2000

We have a small network with a mix of windows 2000 professional(1) and the rest a mixture of windows 95 and 98. Most of the file sharing is from the windows pro 2000 machine. How do you limit who can have access to the shared files? The windows 2000 machine is not a server and does not have active directory. In windows 98 you could password protect a shared file. Does windows pro 2000 have a similiar feature. As a seperate issue, I can access any machine through my network places, but notthrough computer management. Can I add computers or ip addresses this way or is it only through users in active directory. Thanks for your help