I had the same problem (orange light flashing) that no amount of turning off and on again would cure. So I removed the inks and the print head, as described above in this thread. Inverting the head revealed a lot of waste ink - probably the cause of the 'incompatible print head' message that can appear when there is a blockage. To fix the problem apply a few drops of methylated spirit to both the black and colour nozzle areas, taking care not to touch them. This will gently dissolve the surplus ink that can be removed by dabbing a tissue on each of the ink cartridge seatings, where droplets will have formed, as the mixture of meths and ink work their way through the print head. Repeat several times, then replace the head and inks in the printer and leave overnight. Restart the printer and if necessary press the resume button, when the orange light will stop flashing and normal service will resume. If it doesn't, repeat the procedure, to remove any remaining ink residues. As meths is basically neat alcohol this is an ideal solvent and should not harm the intricate passageways of the print head, whilst dissolving any congealed ink that was causing the malfunction. Well worth trying, before rushing off to buy a new print head that costs more than a new printer!
