You can certainly use the Shell function to run the shell. I'm not sure about returning results to Excel though - I can imagine you could do it by outputting the results of the ping to a text file, and using VBA to open the text file and extract the contents.
Instead of using the msgbox, (and assuming you have more than one computer to test), you can feed the return to the adjacent column. The only thing I'm uncertain about is whether you'd need to built a delayed timing loop between each run.
Dim PC As String
Dim Pings, timeout As Integer
Dim Ping_Result As String
For looper = 1 To 1000
If Range("A" & looper).Value = "" Then Exit Sub