Private Sub CheckBox1_Change()
    Dim obj As OLEObject
    Dim wb As Workbook
    Dim ws As Worksheet
    
    Set wb = ThisWorkbook
    Set obj = wb.Worksheets("Лист1").OLEObjects("Checkbox1")
    
    If Not obj.Object.Value Then
        wb.Unprotect Password:="123"
    
        For Each ws In wb.Worksheets
            ws.Unprotect Password:="123"
        Next
    Else
        wb.Protect Password:="123", Structure:=True, Windows:=True
    
        For Each ws In wb.Worksheets
            ws.Protect Password:="123", DrawingObjects:=True, _
              Contents:=True, Scenarios:=True
        Next
    End If
End Sub

    ' Так.    
    obj.Object.Locked = True

    ' Или так.
    'obj.Enabled = False