After four hours with support online I couldn't fix the printer but they showed me how to get to the service menu.
1. Unplug the power cord (!)
2. Insert power plug while keeping power button pressed.
3. While the HP logo appears on the screen, keep the button pressed. The screen will go dark. KEEP THE BUTTON PRESSED for another 5-10 seconds.
4. Let go of the button. The screen remains black.
5. Push Home-Back-Home-Home button. The buttons are usually not visible, so refer to the manual, where they are on the touch screen. (Home is left of the upper left corner of the touchscreen, Back is left of the lower left corner)
6. A blue menu comes up, with four choices.
7. MENU on the lower right has a FULL RESET option.
Unfortunately, it didn't work for me. The printer is still freezing when booting.
My .02 cents: Once you get the printer to actually print it's beautiful. The hardware design is really well thought out. The software design is straight from the 1960s. I am a filmmaker and even I have heard of unit tests... this is really flawed design... (One of their Flash updates is called FaxMemoryFix, so I'll let you imagine the rest) - If you really rely on your printer to work, I would be *VERY* careful before buying one of these.