Open a workbook and then size it to fit just within the application window
Public Sub OpenBook()
Workbooks.Open ActiveWorkbook.Path & "\MyWorkbook.xls"
FitWindow
End Sub
Private Sub FitWindow()
Dim winWidth As Integer
Dim winHeight As Integer
winWidth = Application.UsableWidth 'Get the usable width of app window
winHeight = Application.UsableHeight
End Sub