Try downloading the latest driver for your operating system from Lexmark's website.
Get rid of all the existing Lexmark software and install the latest software. If you are connecting through an ethernet port (not clear from your message) you may have to add a TCP port on your PC to support the printer.
If you are anywhere near Hemel Hempstead I can help (I do this for a living!)
Alan. 07941 364182
Alan
December 2007