What should I do if all the lights on my HP Deskjet F4100 are blinking at the same time?
All lights blinking simultaneously indicates the HP All-in-One has a fatal error. Turn the device off, unplug the power cord, wait a minute, plug the power cord back in, and turn the HP All-in-One back on. If the problem persists, contact HP Support. (Page 7)
From the official HP Deskjet F4100 All-in-One Printer manual, page 7
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