Printing Errors or Lights & Stuck Print Jobs

I have a HP Officejet 7612 Wide Format All-in-One Printer. I am getting the following error message on the printer touchscreen:  

Missing or Failed Printhead

"The printhead appears to be missing, not detected, or incorrectly installed."

When clicking the white backlit question mark to the right of the touchscreen on the printer, it gives me the following message:

Missing or Failed Printhead

Solution 1: Reinstall the printheads. Touch "Show Me" to be guided through printhead installation.

---- I attempted touching the "Show Me" button displayed at the bottom of the original error message on the printer touchscreen, but the printer only makes a beeping sound (like the sound made when the printer turns on and off) and that is the only thing that happens.

Solution 2: Clean the electrical contacts.

---- I removed the ink cartridges and carefully cleaned the gold contacts on each cartridge and then inserted them back into the printer and continued to get the same error message.

Solution 3: Replace the printhead.

---- From my understanding (from the research I have done this morning), it is not possible to replace the printhead on this printer (HP Officejet 7612 Wide Format All-in-One Printer).

Solution 4: Contact HP support.

---- I have googled my problem hoping to find answers on the HP website or on forums, but I have had no luck. The warrinty on this printer just expired back in August. 

IN ADDITION

I have tried to updated the printer firmware from the HP website but it says the firmware for my printer is up to date and I have also tried downloading the diagnostic test from the HP website and that didnt provide help or a solution either.

Can anyone offer any input on what I should do? Is there a way to completely force reset the printer? I had tried several times following the steps on the HP website (unplugging the powercord from the back of the printer and then from the wall and waiting several minutes before plugging back in -and I have the cord plugged directly into the wall-), but I have had no luck. 

What can I do?