The firewall of Windows 2008 R2 and Windows 2012 closes ICMP replies by default. You can enable the ping command with following steps:
1) Go to Start
2) Open a command prompt
3) Type in the following:
netsh firewall set icmpsetting 8
Test it out, the server should be pingable now!
To disable it again, you enter this command:
netsh firewall set icmpsetting 8 disable