Function MenuDis(MenuName, EnDis)
In a module put this:
Dim MyBar
Set MyBar = CommandBars(MenuName)
MyBar.Enabled = EnDis
MyBar.Visible = EnDis
End Function
On a form or where you like put this:
Private Sub Form_Close()
MenuDis "MenuMain", False
End Sub
Private Sub Form_Open(Cancel As Integer)
MenuDis "MenuMain", True
End Sub