How about this, for generating your
fileName
Dim path As String = Environment.GetFolderPath(Environment.SpecialFolder.Desktop)
Dim fileName As String = "new.pdf"
Dim count As Integer = 1
While System.IO.File.Exists(System.IO.Path.Combine(path, fileName))
count = (count + 1)
fileName = ("new_" _
+ (count.ToString + ".pdf"))
End While
Then you can simple use:
Dim strPath As String = Environment.GetFolderPath(Environment.SpecialFolder.Desktop)
.WritePDF(strPath + fileName)