Sub DecocheCheckBox()
Dim CB As Excel.CheckBox
Dim S As Worksheet
Dim i&
Dim col&
Set S = ActiveSheet
For i& = 1 To S.CheckBoxes.Count
Set CB = S.CheckBoxes(i&)
col& = CB.TopLeftCell.Column
If col& = 5 Or col& = 6 Then CB.Value = False
Next i&
End Sub