This printer has worked flawlessly for years. Today I was going to print Christmas card labels and installed a color ink cartridge (the right one). It was brand new. As soon as I installed it the alarm light came on and it displayed U051 Check Ink error code. I normally don't have a color cartridge installed because I don't usually print color, so I took the cartridge out, thinking that the problem would go away. Unfortunately it didn't, and now with just the black cartridge installed (which is fairly new and worked perfectly up to today), the alarm light is still on and I can't access the Settings or Menu options, much less print. I have tried cleaning the cartridge and various other fixes I found online, but nothing works. I would appreciate any advice. Many thanks.
