Print Cartridge Missing

Hi, my printer won't work. I keep getting the error message Printer Cartridge Missing, though the cartridge has been in the whole time. It started when I took the cartridge out to refill the ink; when I put it back in, it gave me the message. I bought a new printer cartridge and tried that as well- still the message. I've taken out the cartidge and put it back in a few times, cleaned the old cartridge's contact with an alcohol swab, turned the printer off and on, unplugged it, etc- nothing has worked. Please let me know if there's anything that might fix it. The printer is only about 3 years old and has been in pretty good shape before this. Thank you!!