Hp 5510 printer display shows ''Print Cartridge Error. See the product documentation for details.'' Cannot find the manual. I have reseated the blank ink cartridge but the message remains.

Sounds like the cartridge head is dirty or damaged. Try cleaning with isopropyl alcahol and a lint free cloth. Don't touch the head with your bare hands

Clean the contacts on BOTH the cartridge and the printer... the little gold dots... try it again.

Note that HP imbeds a serial number in each cartridge and in an effort to thwart refilling, you need to present a different cartridge to the printer and power on when you change. That is, temporarily put a a different one and turn on power to fool it into thinking it is a different one before going back to the one you intend to use...