Your company has client computers that run Windows 7 and client computers that run Windows XP
Professional. You enable the Network Discovery feature on the Windows 7 computers. You discover
that the Windows XP computers do not appear on the network map. You need to ensure that all
client computers appear on the network map. What should you do?

A.
Configure the IPv6 protocol on the Windows 7 computers.

B.
Configure the network shares on the Windows 7 computers to include the user names of all
employees.

C.
Configure the network shares on the Windows XP computers to include the user names of all
employees.

D.
Install the Link Layer Topology Discovery (LLTD) Responder on the Windows XP computers.

Explanation:
http://www.petri.co.il/installing-link-layer-topology-discovery-on-windows-xp.htm
You can use following steps to fix this problem:
1. First you have disable firewall on both the machine.
2. Now download and install Link Layer Topology Discovery (LLTD) Responder package on Windows
XP machine.
To get this click:
http://www.microsoft.com/download/en/details.aspx?amp;amp;amp;
displaylang=en&displaylang=en&id=5577.
3. Make sure that services like Computer Browser, Server, Workstation are started on both machine.
4. Now you have to change relevant settings on Windows 7 computer:
a. First open “Control Panel”
b. Now double click on the “Network and Sharing Center” and then select “Advanced sharing
settings”.
c. Now expand the current network profile and then choose following options:
“Turn on Network Discovery”,
“Turn on file and printer sharing”,
“Turn on sharing so anyone with network access can read and write files in the Public folders”,
“Turn off password protected sharing”
5. Now you have to write the computer name for Windows 7.
Now go to start button > now open Run in Windows XP and then type “\\Windows 7 computer
name” and press enter. Now you are able to access Windows 7 computer from Windows XP.