HP 970CXI Prints ''self-test'' only. No ...

I have a HP Deskjet 970CXI. It will print a ''self-test'' page if you remove and replace the cartridge only. It will not print any documents. When you first tell a document to print the printer icon will appear in the bar at the bottom of your screen for not even a second until it disappears. And then, nothing. No error messges. The green light is on the printer. I've checked connections etc. I've gone into the control panel, and it says the printer is ready. Any advice?