canon mp480 printer....wont!?

hello, above printer has decided that it has no ink. I changed the cartridges about a week ago however! refilled them at cartridgeworld put them back in and the printer worked (have only printed out about 10 pages!) even though the printer was indicating LOW INK!! It has now decided that it has run out of ink. the display on the printer is saying 'U163 ink has run out. replace the ink cartridge'.( it can't have!!?) taken them out, put them back in, turned it off and on again but nothing happening screen on the printer still displays the message & pressing any of the buttons on the printer doesn't do anything!! help! read the reply for someone called gareth who seems to have exactly the same problem whih his canon printer - no good..... any assistance etc etc!
thank, Holly