Hello and Welcome to TSF,
Go here:
http://downloads.lexmark.com/perl/do.../downloads.cgi
Note: you will need driver, firmware, software, utility
where it says "Choose another download type"
1. unplug usb cable from printer, leave printer on
2. install MPWN2K5E.EXE
3. plug in the usb cable when the installation tells you to
4. after it completes, reboot pc
5. install the other necessary software, utilities also.