Re: the touch screen on my C4780 photosmart print is Blue with a number B853A414

Welcome to the HP support community.

Remove the ink cartridges, and reset the printer

1. Remove the ink cartridges from the printer.

2. With the printer turned on, disconnect the power cord from the printer.

3. Unplug the power cord from the power source.

4. Wait at least 60 seconds.

5. Reconnect the power cord to a wall outlet and to the printer.

   NOTE: 

   HP recommends plugging the printer directly into a wall outlet.

6. Turn the printer on.

7. Reinsert the ink cartridges, and then close the ink cartridge access door.

8. If you receive a prompt to print a calibration or alignment page, do so.

You can refer to this HP document for more assistance:- click here

I hope that helps.

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Cheers.