The correct model number is N1240
U (not N124ou). The 5th digit is a zero, not a lower case letter oh.
You can find drivers on the Canon website: http://forums.driverguide.com/showthread.php?t=58366
And you might also find this driver (in our driver database) by using our Simple Search Wizard
(found within the HOME button/page at the upper left corner of this page).