Excel 2007 takes forever to export Data

I have a macro that is used to export data to a ~ delimited file. The macro runs fine with Excel 2003. However when we try to use it in an excel 2007 file it takes forever to export the data. I.E. in excel 2003, I can export 65k rows of data in just 6 minutes. However it took 53 minutes to export 45k rows in excel 2007. I would appreciate any help with solving this issue. The macro code is below:

Sub Export_Local_TP_Source()
'Delete existing tp_source.txtx file

On Error Resume Next
Kill "c:\temp\TP_source.txt"
On Error GoTo 0


'
'Start of actual export
'Public Sub CharacterSV()
        Const DELIMITER As String = "~"
        Dim myRecord As Range
        Dim myField As Range
        Dim sOut As String
        
        Open "c:\temp\TP_source.txt" For Output As #1
        For Each myRecord In Range("A2:A" & _
                    Range("A" & Rows.Count).End(xlUp).Row)
            With myRecord
                For Each myField In Range(.Cells, _
                        Cells(.Row, Columns.Count).End(xlToLeft))
                    sOut = sOut & DELIMITER & myField.Text
                Next myField
                Print #1, Mid(sOut, 2)
                sOut = Empty
            End With
        Next myRecord
        Close #1
    'End Sub
'end of export
MsgBox "File exported to: c:\temp\TP_source.txt", vbOKOnly

End Sub

Hi

Although not much consolation I have found the same thing happening, with macros running much slower than in previous versions, around 10 times slower on average.

I have not been able to find any way to speed things up.

Regards

Jeff

Well I think it has something to do with the way it is calculating the number of columns.

I tried the following to see how many rows/columns it was counting

sub test()
 rn=(range("A" & Rows.count).end(xlUp).row)
 cn=columns.count
 msgBox ("rows - " & rn & ": Columns - " &cn)
End Sub

It returns a total of 16384 columns even thoul I am only using 15.

I tried to use

cn= range(.cells, cells(.row, columns.count).end(xlToLeft))

to count the columns but it errored.

If this is the case, how can I tell it only to use the used columns (15 in my case) without hard coding 15?