I just received a new HP deskjet 450ci.... when I plug in the AC adaptor and power it up the POWER LED goes off after about 3 seconds. If I press the power button again the printer proceeds to start flashing/cycling through all of its LEDS. I looked this up in the manual and that flashing cycle means there is a Printer Error. I am trying to load the ink cartridges, but I can't get the printer to power up properly and the ink trays do not move to the load position. Similarly, when the printer goes into the Printer Error mode none of the buttons work and the only way to turn it off is to unplug the AC adaptor.