ASPX page does not render PDF in IE7 and Chrome on Windows XP

Question

I have an .aspx page that returns a PDF. Below is the code on Page_PreRender.

Protected Sub Page_PreRender(sender As Object, e As System.EventArgs) Handles Me.PreRender

    Dim pdfStream As MemoryStream
    pdfStream = CType(Cache("PdfViewerContent"), MemoryStream)

    Response.BufferOutput = True
    Response.ClearContent()
    Response.ClearHeaders()
    Response.AddHeader("Cache-control", "no-store")
    Response.ContentType = "application/pdf"
    Response.AddHeader("Content-Length", pdfStream.Length.ToString())
    Response.AddHeader("Content-Disposition", "attachment=PDFFile.pdf")
    Response.BinaryWrite(pdfStream.ToArray())
    Response.Flush()
    HttpContext.Current.ApplicationInstance.CompleteRequest()

End Sub

This page is launched from a window.open javascript call.

This works fine on Windows 7 with IE9, Chrome, and Firefox. However, on Windows XP running IE7, the browser just flickers and no window is opened. (Popup Blocker is disabled) With Chrome I get an error in developer console "Resource Interpreted as Document but transferred with MIME type application/pdf" and the page is downloaded as a file.

Answer 1

I believe it should be

 Response.AddHeader("Content-Disposition", "attachment; filename=PDFFile.pdf")

Also, I would call Response.End() just after Response.Flush()