Communications :: Write A Program To Ping Computers On Network To See If They Are Turned On?

I am trying to write a program to ping computers on my network to see if they are turned on. So far i have the following:

Code:

If My.Computer.Network.Ping("192.68.0.5") Then
MsgBox("Computer is on.")
Else
MsgBox("Ping request timed out.")
End If

If i use ip addresses, this works fine but i would rather use hostnames due to the ip addresses being dynamic (something which is outside my control). Using the hostname, it reurns "Computer is on" if the ping is successful, but if the hostname cannot be found, instead on returning "Ping request timed out", an error occurs as follows:

A first chance exception of type 'System.Net.NetworkInformation.PingException' occurred in System.dll