Hi Guys, hope you are able to help, ran out of ink (colour) on an HP Deskjet 840. Changed cartridge but printer would not work. No ink light flashing. Changed it again for another cartridge ink light went out but when I tried to print in colour there was a colour missing STILL, the blue . The red and yellow are faint but working. Have cleaned the printer and the heads of the cartridge, have also been on the HP site and run a diagnostic page which came up with an error code of 90020103 but I cannot find any reference for it online (HP) anywhere. Hope you will have some experience with this as I will have to buy another printer if I cannot get this to work it's needed for coursework for my son. Thanks in advance.