I had the exact same problem, disabled windows firewall and same problem.
Turned out to be Netbios over TCP/IP, I had it turned off on my laptop.
If it is disabled, it will not work. On a peer to peer network there is not a DNS server. I thought IPv6 would take care of it, I even changed the bindings for the LAN connection so IPv6 was higher than IPv4, would not work if NetBios over TCP/IP was disabled.