protecting shared files

I'm having some trouble with sharing files from my Mac. On my network is my Macbook, a Vista machine and an XP machine. I managed to get them all connected just fine, but the problem is that from my two windows computers I can see *all* of my Mac's files. I literally see a folder called "Macintosh HD" which is the / directory. This is actually kinda nice while I'm at home, but I'm very paranoid about when I go on public networks that my Mac is wide open. I'm not logging into my Mac from the windows machines, it never asks for a login.

I really am not certain what I'm doing wrong. In the Sharing Preferences, I only have File Sharing checked. The only listed shared folder is my Public Folder, where I have Read & Write, Users have Write Only (Drop Box) and Everyone has No Access.

In Options I have AFP and SMB enabled, AFP was enabled by default and I enabled SMB due to some instructions on getting Vista to see my Mac.

I'm probably missing something stupidly obvious here, but can anyone help?

Thanks!

 

No one with any ideas?

 

Come on someone must know about this... should I post in another forum?