In VBA: how to open a workbook with a specific version of excel?

[Cheetahke]

Hi,
I have Office 2003 and 2007 on my computer. I've written code in VBA (Excel
2003)for opening a workbook if the file exists. If not, a new workbook must
be created.
The new workbook is created and opens, but the old workbook opens a second
time in Excel 2007. How can I prevent this in VBA?

Code:
If fileExists("filename") then
Set nWB = WB.Open("filename")
Else
Set oWB = active.workbook
oWB.save
oWB.saveCopyAs ("filename")
Set nWB = wb.Open("filename")
End if