How to perform system reset for a HP C7180 ink system error. Posting this up for anyone who is searching for the same answer. With the printer on, press and hold the '*' key on the key pad, then press the '#' key and release them both. Enter '123' to enter maintenance mode. Press the right arrow to scroll to the System Configuration menu Then pressed OK to clear the error condition Once cleared, press cancel to return to the menu. Then powered off and back on and go to Setup -> Tools to Clean Printhead. This will clean and print a test page. Done! This may work for other HP printers, not just the C7180.