I'm sorry about the issue. Is the printer connected the computer with a USB cable? Or is the connection wireless?
If it is wireless, what's the status of the wi-fi/wireless icon / light on the printer? Are you able to go to the wi-fi/wireless setting on the printer and connect it to your wi-fi/wireless network name?
Can you please click on the Apple logo / menu, then click on "About this Mac...", then check your Mac OS X version, i.e., 10.6, 10.7, 10.8, etc.?
When you are available, please reply at the box below to continue. Thank you.