HP Desk Jet 6540 (8963A) Tri-color Cartridge not recognized. Clean contacts in ink print head, on cartridge, change 3 new cartridges; I try with and without connection to computer. How can I find out if problem is in the printer? Could the spring on the side of the inserted cartridge affect the contacts with the print head? Should I reinstall the program? Can I reset the printer memory? Thanks for reply.