Is the figure you are showing of the CSV file as it looks in notepad , or as it looks when opened in Excel?

I am assuming that its a CSV with no header. So you can load it with

lcStr=FILETOSTR(YourFileName)
*Add a headline
lcStr="a,b,c"+chr(13)+chr(10)+lcStr
*Create a temp csv file 
STRTOFILE(lcStr,'temp.csv')

and then use the code Anders has given you

Regards
Tushar
>
> Sub ok()
> Dim a As Range
> Dim rng As Range
>
> Set rng = Range(Cells(1, 1), Cells(Rows.Count, 1).End(xlUp))
> For Each a In rng
> If a.Value = "0125" And a.Offset(0, 1).Value = "FDC" Then
> a.Offset(0, 1).Value = "IDC"
> End If
> Next
> End Sub
>
> Thank you, Thank you