Timer for sheet

DoEvents just allows the code to delay to run other things (I don't find it helps a lot most of the time), however, the method you are looking for should be something like this... round, 2 gives seconds which is why I've made it stop at 120. I put >= in case it is 121 seconds for some reason... if we stop only if =120 then if we miss 120 exactly it will never stop:

Sub start_timer()

Dim t
t = Timer
Do
    DoEvents
    If Round(Timer - t, 2) >= 120 Then
        Sheets("start").Activate
        Exit Do
    End If
Loop

End Sub