This is plagerized from Yahoo Answers, contributor "Richard J"http://answers.yahoo.com/question/index?qid=20101019074723AAQrKA1
"See if this will help you
1- Remove all ink cartridges from the printer, both black and color, new or refilled.
2- Turn the printer off by pressing the Power button. Let the printer stay off for 20 seconds.
3- Turn the printer back on. Allow the printer to go through the usual start-up process and recognize there are no cartridges installed.
4- Repeat Steps 2 and 3 until the printer has been turned on and off five times. This process resets and removes the last five ink cartridge IDs used from the printer's memory, allowing the printer to believe the refilled ink cartridge is new.
5 Replace the ink cartridges and attempt to print."
That looks to be a good starting point.