VBA: how to hide rows if a cell contains a certain text

I am using Excel 2013. I am new to VBA. I found a code that would simply hide 2 rows (36 and 37) if my cell N39 is equal to "Passed"

I found that code but I receive the message "ambiguous name detected "Worksheet_Change" Private Sub Worksheet_Change(ByVal Target As Range) If Range("N39").Value = "Passed" Then Rows("36:37").EntireRow.Hidden = True ElseIf Range("N39").Value = "Failed" Then ows("36:37").EntireRow.Hidden = False

End If

End Sub

so I tried the name of my worksheet but it does nothing

Private Sub NRF(ByVal Target As Range) If Range("N39").Value = "Passed" Then Rows("36:37").EntireRow.Hidden = True ElseIf Range("N39").Value = "Failed" Then ows("36:37").EntireRow.Hidden = False

End If

End Sub

Any idea of what I am doing wrong?

Thank you