I have blogged about this before and I will again as folks fall trap to this all of the time.
By default, ping response is disabled beginning with Server 2008 and continuing into newer revisions of Windows Server.
FYI - With Server Core, ping is silent regardless of the state of the firewall.
Here is a great tip from Ben of the Hyper-V team:
The first thing I would do is to check the firewall configuration in your guest operating system, and make sure that it allows ICMP.
Here is a great article that steps you through how to do this:
“Nobody can ping my computer”