Option Explicit
Private WithEvents App As Application

'Назначаем значение переменной App
Private Sub Workbook_Open()
      Set App = Application
End Sub

Private Sub App_SheetChange(ByVal Sh As Object, ByVal Target As Range)
    Dim objSh As Object
If Sh.Name = "Лист1" Then
   If Not Intersect(Target, Range("K5:K7")) Is Nothing Then
     If Target = "Сигнал" Then
Set objSh = CreateObject("Shell.Application")
objSh.Open ("C:\Users\Максим\Music\1.wma")
     End If
  End If
End If
End Sub