Cold reset is resetting printer to the factory default setting. Any setting at ehe printer control panel will be reset to factory default setting. A cold reset does not clear the values in the service menu, such as the serial number and the page counts.
How to Perform a Cold Reset HP LaserJet 4345 MFP

* Turn the HP LaserJet 4345 MFP off and then on.
* When the memory count appears on the control-panel display, press and hold 6 until all three LEDs flash once and then stay on. This might take up to 20 seconds.
* Press 3 four times until COLD RESET appears on the control-panel display.
* Press 6 one time. The HP LaserJet 4345 MFP should continue its initialization sequence.

By performing cold reset all setting on the HP LaserJet 4345 MFP are also reset. Before performing cold reset be sure to print a configuration pada and menu map.