Windows 2000 Server

I need advise please….

I setup a LAN consist of 20 PC No server just a peer to peer network, what happen is when i share a folder on one pc and share it the other pc’s then mapped the shared folder, it only allows 10 users to mapped that drive (Question No 1)

Now i am planning to setup a Windows 2000 server, but when i try to connect one of the client(Windows XP) it changes everything even the desktop settings which i dont want to happen. I just want a server that will serve as a domain controller which will share a folder and all 20 clients can mapped drive.

Please be informed that the server will also be my machine and there i will do all my work.

Thanks in advance….

PAUL