If your HP Officejet 7100 all-in-one printer will not turn on or fails to clear error messages after components are replaced, you may need to access the device's battery. Removing the battery for a period of time resets the device. If you continue experiencing problems, replace the battery entirely. Be aware that these actions wipe settings saved on the printer, and the data cannot be restored after removal.
Clear any print jobs. Unplug the printer's power cord.
Look for the battery compartment on the front of the printer at the bottom left-hand side.
Open the compartment and remove the battery from its casing with tweezers.
Leave the battery out of the compartment for 24 hours.
Replace the original battery or place a new one into the compartment.
Turn the power back on and reset the printer's settings.