You need to name the range where these answer are going to be located. I named that range "Answer". The name of the range must match the entry in the code:
Private Sub Worksheet_Change(ByVal Target As Range)
If Intersect(Target, Range("**Answer**")) Is Nothing Then
ElseIf Target = "" Then Target = "No Answer"
End If
End Sub
You can name the range anything you want but it then you must enter that name in place of the bolded entry in the code above.
You name a range by selecting the range in the spreadsheet and then clicking on the Name box and typing the name into the box and pressing Enter.

In this figure I have named the range A1:A10 Answer.
If you already have a name Answer, but referencing a different location than where you want it, choose Formulas, Name Manager select the name and Delete it. Then add your new one as I described above.