HP Printer

I have a HP officejet Pro K850 printer. It takes 4 ink cartridges. A week ago the black cartridge ran out and I replaced it with a new Hp cartridge. Since then, everytime I print a document it prints a test page. I have reinstalled the driver but it has not worked. I must say the yellow cartridge was low too but still had some life in it. But after 100 pages test prints, both the yellow cartridge and printhead have gone south and need to be replaced. Now, the printer does not print anything and it is becuase it wants me to replace the printhead and cartridge. Should I change them or trash this one and buy a new printer?