Enable ping response in Win7

Control Panel --> System and security --> Windows Firewall --> Advanced settings --> Inbound rules --> New rule --> custom rule

in Protocol and ports: Protocol: ICMPv4 
on the same panel go to customize, choose "Specific ICMP types", check the box "echo request"

Reference link
http://answers.microsoft.com/en-us/windows/forum/windows_7-networking/how-to-enable-ping-response-in-windows-7/5aff5f8d-f138-4c9a-8646-5b3a99f1cae6

Check and Set DNS server using nslookup

#nslookup

Check the DNS the following URL uses:
>trailers.apple.com

Set DNS server:
>server <DNS IP>

Check again:
>trailers.apple.com

Change MAC address in Windows

1) go to "Local Area Network Properties"
2) click "configure"
3) Choose "Advanced" tab and select "Locally administered address"
4) Input target MAC address into "Value" field
5) done

Reference links
http://www.online-tech-tips.com/computer-tips/how-to-change-mac-address/