Try the self-test for your printer -|
If this does not match the dots on the cartridge, you have either a bad cartridge or printer. You can get bad cartridges out-of-the-box.
If certain colors do not print but there is still ink in the cartridge, the nozzle is clogged. I have never used these but have heard users who unclogged nozzles by sitting the cartridge is a saucer of water for several minutes. Also have heard reports of cleaning the nozzle ports with a q-tip dipped in alchol. Neither of these is "school" approved but probably worth trying before you discard a cartridge.