We have a Lexmark MS415dn printer connected via USB to a PC running Windows 7 Professional. I cannot print to this printer because when I try, on the LCD display it says "load tray 1 with plain paper letter." I have checked the settings for this printer. Tray 1 is the default and the paper type for that tray is plain, letter-sized paper. I have no idea why it keeps giving me this message.
Open the paper tray, ensure there is paper, and ensure that the guide bars are set to the appropriate size.
-Sean