You definitely need NetBEUI as this is the protocol that does "the sharing" in a Windows Network.
It's possible to set up a Windows Lan without it, and just use "Netbios over TCP/IP" option, but I've always found it unpredictable to say the least.
Larger networks (eg in a call centre or similar) will have SMB servers, WINS servers and other such delights. In such cases you don't need NetBEUI as the servers will take care of address and share resolution.
TIP - you really should password protect your shares if you are accessing the Internet on a PC with shared resources (like Dad). It's not enough to simply rely on your firewall (which I hope you've installed!!). Your password for the shares should be at least 8 characters long including numbers and letters! If your firewall software fails to load correctly or breaks somehow, your password is your last line of defence against somebody having direct access to your c: drive!
Cheers
GE