Run macro (Private Sub) when checkbox is checked

I've got the following macro to select the entire row when the active cell is selected. That's working perfectly! However, I just want to make this macro working when a checkbox is "checked"

Private Sub Worksheet_SelectionChange(ByVal Target As Range)

If Target.Column <> 1 Then
    Exit Sub
Else
    Application.ScreenUpdating = False
    Cells.Borders.LineStyle = xlLineStyleNone
    Rows(Target.Row).BorderAround Weight:=xlMedium, ColorIndex:=3
    Application.ScreenUpdating = True

End If

End Sub