The alarm light continues to

The alarm light continues to flash and although the LCD message says to "check printer press resume key" I don't seem to be able to do anything to get it to stop. I've tried turning the printer off, unplugging it for 15+ seconds and turning it on again only to get the same message. When I open the hood in order to access the print cartridges, the printhead unit does NOT return to the center so I cannot access them or do anything to check them. I don't know what to check. All of this has come about because I've been trying to get the colors to correctly print and before running into this problem, I replaced the black ink cartridge and used 99% isopropyl alcohol to drop onto the printheads after removing the cartridges. After doing this I've tried to print nozzle check patterns and test pages with pretty much nothing coming out on the paper.