If you never receive responses to pings sent to Vista machines, Windows Firewall may be blocking ICMP Echo Requests. So if you are trying to troubleshoot network problems and ping a Vista machine, you should double-check the firewall setting.
Open the Windows Firewall with Advanced Security utility by typing “firewall” into the Start menu search box. Select the Incoming Rules and find the File and Printer Sharing (Echo Request – ICMPv4-In” rule. Then enable it, for the desired profile.
Eric Geier is an author of many wireless networking and computing books including Home Networking All-in-One Desk Reference For Dummies (Wiley 2008) and 100 Things You Need to Know about Upgrading to Windows Vista (Que 2007).