VBA to automatically return a value when codition is met.

[spittingfire]

Hi All,

I have the below simple VBA script that works well on it's own

Sub fill()
If UCase(Range("F3")) = "NO" Then
    Range("F4").Value = "000-0000-0000"
End If
End Sub

However what I want to do is to have it execute automatically the value of "000-0000-0000" when F3 is "NO"

I tried changing the VBA to

Private Sub Worksheet_Change(ByVal Target As Excel.Range)
If UCase(Range("F3")) = "NO" Then
    Range("F4").Value = "000-0000-0000"
End If
End Sub

and putting it into the sheet name but it just causes excel to crash and close.

So clearly I am doing something wrong and need some help fixing it.

Thanks in advance for any help you can provide.