protect files on my server

My server is Windows 7, and clients of the LAN are Windows Vista and Windows 7. Now I need to avoid that some users of a client computer access to some shared folder in server. Some clients can access but can't modify, some can print but can't modify and some can only view. I know that the best way to achieve this is by Windows Server Operating system, but I can't get it so I need something based on free software. I think the solution may come from setting a password to that folders.

Is there a better solution?

 

On your Win 7 Server, go to Start -> Help and Support and type in limit access to files and folders. The second item is the att'd screen capture. It should give you the info you need to accomplish what you want without needing third party software.