הצלחתי 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Net.NetworkInformation;
using System.Net;
using System.IO;
namespace WebService2
{
/// <summary>
/// Summary description for Service1
/// </summary>
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
//
public class Service1 : System.Web.Services.WebService
{
public string SimplePing(string PCname)
{
Ping pingSender = new Ping();
string status;
try
{
PingReply reply = pingSender.Send(PCname);
if (reply.Status == IPStatus.Success)
{
return "True";
}
else
{
return "False";
}
}
catch (Exception Error)
{
status = Error.InnerException.Message;
return "False";
}
}
}
}

* לשעבר בכינוי Computerman