If a cell in COL O changes, I want to clear the contents of COL P, Q R (in
the same row)
If a cell in COL Q changes, I want to clear the contents of COL O, P, R
(again in the same row)

I think I had the following working in Excel 2003, but its not working in
2007.

Private Sub Worksheet_Change(ByVal Target As Excel.Range)

With Target
Select Case .Column
Case 15 'column O
Application.EnableEvents = False
Cells(.Row, "P").ClearContents
Cells(.Row, "Q").ClearContents
Cells(.Row, "R").ClearContents
Application.EnableEvents = True
Case 17 'column Q
Application.EnableEvents = False
Cells(.Row, "O").ClearContents
Cells(.Row, "P").ClearContents
Cells(.Row, "R").ClearContents
Application.EnableEvents = True
End Select
End With

End Sub