put usb device in to scan a paper and an error message saying " unknown device: disconnect device. refer to printer documentation to troubleshoot". the owners MANUAL was no help; i tried a different usb device, rebooted the printer. the same error message is on the printer's screen. i can not even print anymore b/c i can't get the error message to go off of the printer's screen. i've looked at many forums, u tube and other sites, but nothing hashelped. i'm starting to lose my mind and any help would be appreciated.
thank youAre you plugging it directly into the printer ? ?
What happens if you plug it into the PC....can you see the file and print it from there ? ?yes i am plugging the usb device directly into the printer. at this point, the printer does nothing..it displays the error message all the time and the ! is blinking. when i plug the printer cord into my COMPUTER, it won't let me do anything either.
Did the printer come with a CD (drivers etc)If the printer connects via USB try the following:

Unplug and disconnect the printer from the PC.
Go to Device Manager or printers in Control PANEL...locate the printer and select remove/uninstall.
Re-boot.
Go to Add/Remove Programs...locate the HP application and remove it.
Re-boot.

Now install the printer SOFTWARE using the HP CD...
Do NOT connect the printer until the software prompts for it.

Best of Luck.