We ran into a peculiar issue today at work were we had a new laptop that simply could not see other computers on the network.  We could ping them by IP address, but no name resolution was occurring.  We troubleshot it as one normally does (e.g. making sure that the DNS server was right, checking NetBIOS settings, etc, etc).  Upon running ipconfig /all, however, we saw that the Node Type was set to Peer-Peer rather than Mixed or Hybrid.

This setting cannot be changed via the Windows UI (at least not as far as I'm aware), but you can set it in the registry.

All we had to do was open the registry (via regedit, regedt32, etc) and change the following setting:

Key:     HKLM\SYSTEM\CurrentControlSet\Services\NetBT\Parameters
Setting: DhcpNodeType
Value:   8

Valid values include 1 (Broadcast), 2 (Peer-Peer), 4 (Mixed), and 8 (Hybrid).

Once the box was rebooted all was hunky-dory.