Any quick ways to change #N/A results to 0

With 2007, have a look at the IFERROR() function.

@ Shg doesn't that just overwrite all the folmulae that return errors with 0?

Ctrl+G (Soto), Special, Errors. Type 0 in the formula bar, press and hold the Ctrl key, then press Enter.

You can change the formulas or change the values. I don't know of a third alternative.

A brutal way would be to use VBa

Select the range that you need to wrap all existing formulae in IFERROR() then run this macro

Option Explicit

Sub WrapInIFERROR()
    Dim Cell As Range
    For Each Cell In Selection
        If Left(Cell.Formula, 1) = "=" Then
            Cell.Formula = "=IFERROR(" & Mid(Cell.Formula, 2, Len(Cell.Formula)) & "," & Chr(34) & Chr(34) & ")"
        End If
    Next
End Sub

This could be refined if required, as it stands it will mask all errors.