You need to download the DRIVER - a piece of software that sits between the operating system and the device - to make it work.
The Lexmark site will provide it for Free - just match the model number with your operating system XP - Vista etc.
Some naughty sites apper to offer drivers but want payment - avoid them.
http://support.lexmark.com/index?page=home&locale=EN&userlocale=EN_UK&segment=DOWNLOAD
Good luck
Peccavi
January 2010