A questo punto fai prima ad incapsulare tutto in una funzione...
codice:
Public Function GetFileLine(ByVal FileName As String, ByVal RowNumber As String) As String
    Dim c As Integer, fn As Integer
    fn=FreeFile
    Open FileName For Input As #fn
    Do Until EOF(1) Or c = numeroriga
        c = c + 1
        Line Input #fn, GetFileLine
    Loop
    If EOF(fn) Then GetFileLine=""
    Close #fn
End Function
Richiamala in questa maniera:
codice:
Dim riga As String
riga=GetFileLine("c:\nomefile.ext", 3)