In Windows 7 when you are in a workgroup ping replies are disabled by default in the Windows firewall. One way to get around this is to disable the firewall but this is really only a good idea if you are in a lab environment. Otherwise you want to keep your firewall always turned on and instead create a rule to allow echo requests inbound
Windows 7 Firewall ICMP Rule
Windows 10 Firewall ICMP Rule
In Windows 10 this is a bit easier as the rule already exists and we just need to enable it