Segue um código que cria uma msgbox com tempo:
Public Function MsgBoxTimer(Seconds As Integer, Prompt As String, Optional Buttons As VbMsgBoxStyle = vbOKOnly, Optional Title As String) As VbMsgBoxResult
Set WShell = CreateObject("WScript.Shell")
MsgBoxTimer = WShell.Popup(Prompt, Seconds, Title, Buttons)
End Function
Public Function MsgBoxTimer(Seconds As Integer, Prompt As String, Optional Buttons As VbMsgBoxStyle = vbOKOnly, Optional Title As String) As VbMsgBoxResult
Set WShell = CreateObject("WScript.Shell")
MsgBoxTimer = WShell.Popup(Prompt, Seconds, Title, Buttons)
End Function