I did some research and found out that lexmark doesn't offer updated for the z600 anymore. They have them for the z611 but who knows if they would work on your printer you can give it a try, here is the download:
Create a new folder on your desktop and name it newhpdrivers(substitute your manufacturer in new name).
Un-intall printer and printer software completely.
Go to manufacturers website and navigate to their drivers/downloads or support menu.
Select your model, choose the relevant software and download to the new folder you created on your desktop(watch for the light yellow bar at the top of window viewing pane, click on this and choose – download file - .
Power down your computer.
Reconnect the printer to the computer and turn printer on.
Power on pc.
Windows will detect new hardware and ask if you have the manufacturers install cd or a location to check for install files.
Direct the wizard to your new software, follow the rest of the setup instructions and your done.
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