Remove the cartridges, snap the printhead lever on the right side of the cartridges down, tilt the printhead forward and you should be able to remove the printheads. Soak the printheads in distilled water after you run them under running water until the water runs clear. If this doesn't work, after drying, you should reset the EEPROM on the printer and I can walk you through that as well.
Please explain what part is giving you problems.
Okay, but when the printhead carrier moves to the center when you open the top, you can unplug it. Generally, I rarely need to remove the printhead, only turn the power off, remove the cartridges and use q-tips (cottonswabs) and rubbing alcohol to clean them. Rarely does it require removing them. If that doesn't work, I then remove then.
But if you give up, nothing I can do about it.