Try printing a test strip to see if all your colours are being printed.That way you can see if the printer is working.There will be a test facility on your printer properties,or I use paint and make squares of red,green,blue,yellow and black.If they come up a different colour you will have a clue where your problem lies.
silly question but have you checked your cartridges arent running out of ink. i printed out some photos recently and the ink was low but this didnt show up on the ink level indicator. changed the cartrdige and job done.
Check the colour content in your cartridge.I had a similar problem with a tri-colour cartridge, and found that the blue was the problem, due to low capacity, as per accord solution.Change the cartridge.