On a stric Intranet do you need the following items without email services;

Drivers

Direct Parellel
Intel R Pro 100
VE Network Connection
WAN Miniport IP
WAN Miniport L2TP
WAN Miniport PPTP

No Internet on system

depending on what your network is using for protocols. for instance pptp and l2tp are vpn protocols. you likely wont need unless you get outside access in.
direct parallel i also doubt since you likely use a network card for your lan. your intel r pro, is your network card, yes you should keep.
this is general i know, but i dont know your logical topology. if there is no reason to dump them, leave them.
thats my advice anyway.
dave

thanks