PING is a useless test for this condition.
I'll refer you to a Vista Page, but everything except the Public vs Private comments
apply to ALL Windows systems.
For firewall control, you need special ports to be allowed, but only for YOUR lan addresses.
IF your lan is 192.168.1.1 thru 192.168.1.255, then
Code:
allow TCP/UDP in src iprange 192.168.1.2-192.168.1.255 ports 135-139,445
allow TCP/UDP out dest iprange 192.168.1.2-192.168.1.255 ports 135-139,445
allow UDP in src iprange 192.168.1.2-192.168.1.255 port 631
allow UDP out dest iprange 192.168.1.2-192.168.1.255 port 631
the first two are file sharing and will work for Mac, Linux and Windows,
the last two remote print spooling