|I don't know where to start. I think you need a primer on how to setup a LAN and how to setup shares. |
Everyone needs to have a login and each person needs to have access and restrictions set by the administrator.
Below is one MSKB article that can get you started. WinXP has help files that should explain everything.
As far as seeing the other computers goes, are they all connected to the same network? If you are going to share a printer and want to share some files it may be best to dedicate a computer to serve as a file and print server. If you have less than 10 users that should work OK. If more than ten users you may need a different version of Windows and should definitely have some type of server.
Other more knowledgeable help will come along and add to my meager comments.
Suffice to say you are going at this the wrong way, IMO.