I have a Canon S450 that isn't working. It gives a series of blinking lights--one long green and six shorter yellow/orange lights. Does anyone know what this means?

On most Canon's printers 6 orange flashes means a temperature sensor error, I don't know what is the meaning for your model, there could be another reason - printer could not recognize the print head due to one or another reason. Search the net for ERROR CODES for your printer. You may also try to reset the waste ink counter, this also could be the reason for stopping work.

ERROR CODES FOR CANNON S450

The printer will not print.

RROR CODES FOR CANNON S450

Why will the printer not print?

6 orange lights means that your printer cannot recognize the prtint cartridge, that's why the printer will not print. Take out the print cartridges and you'll have the same error again. The only way is to replace it with another one or to buy another printer.