As already said before, you don't need any "samba protocol" on your XP machine. You only need to correctly set up your /etc/samba/smb.conf file. Lok for parameter
workgroup = your_group
and change the "your_group" to the name of your windows group. If you need you can set up also parameter
guest account = nobody
It allows all windows users to browse and use your sharing without any passwords or users' logins. At the end of this config file you can see some examples how to share some directories or printers to Windows users. Try to modify it to fit your system configuration or let it be as defined. After that try to re-run samba service and check if something is shared by default:
You should see some sharing. Then go to your Windows machine and try to browse Neighbor's computers. If you see your Linux machine as some Samba server, you won. If not. Try to Search the network for Linux machine's IP.
If you cannot find the Linux machine, you have a problem with your network.
I hope, it will help you.