I upgraded to Snow Leopard OS from Leopard, and then to Lion (OS X) on my MAC. My HP C4280 scanner used to work in all modes with the original operating system, but now it does not. I downloaded the new driver for the OS X and am able to print from the computer and the scanner, but I am not able to send things back and forth between the printer and the computer. The printer displays the message "USB not connected." One piece of advice I saw was to uninstall the printer software and drivers, shut down my computer, and reinstall them via google after bringing the MAC back up. Is there something else? I have already moved the USB connector to each of the three available ports on the computer, with the same result.