Booting problem when power up after 2/3 seconds black screen comes up with "password =" in top left corner, won't accept any of my password and powers down after 3 attempts

To adjust the touchscreen sensitivity, perform the following:
1. Power the copier OFF.
2. Access the Key Operator Mode (Power the copier ON, while pressing the [HELP] key).
3. Touch [10. Control panel adjustment] on the touchscreen to display the control panel adjustment screen. Note: If the touchscreen is so far out of adjustment that there is no response when touching [10. Control panel adjustment], the control panel adjustment can be accessed (at this point) by touching any numeric key on the 10-key pad.
4. Touch the + at the upper right corner of the touchscreen lightly with a touch pen (something with a round tip which is made of resin is recommended as a touch pen). Check the coordinates displayed in the top line at the top of the touchscreen.
5. Ensure the X coordinate and the Y coordinate displayed in the message area fall within the standard values. The acceptable values are on the second line.
6. If the values are not within the acceptable parameters, repeat Step 4 until the values are acceptable.
7. Touch the + at the lower left corner of the touchscreen lightly with a touch pen (something with a round tip which is made of resin is recommended as a touch pen). Repeat the process used for the upper right coordinate until acceptable values are achieved.
8. As verification of a correct adjustment, touch the [CHECK] icon at the upper left and lower right corners. You should hear a beep tone for each one. If a beep tone is not heard, repeat the adjustment.
9. Power the copier OFF/ON to exit the Key Operator Mode.

From the description the hard drive has failed or windows has corrupt files. Unplug power supply from laptop and remove main battery, press and hold power for 2 minutes to remove residual voltage. when finished install battery and power supply now power up.

Hello
Same problem for me. found a procedure to get back to Service Menu which works for HP 8600 :
https://h30434.www3.hp.com/t5/Printers-Archive-Read-Only/X476dw-doesn-t-boot-Help/td-p/5044674
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.

If you press Ctrl + Alt + del, does it bring up an unlock screen where you can enter your password? If not, can you press and hold the power button for 10 seconds to shut it down? Then power back on to restart.

try removing all cables connected to your tower, (including power cable, mouse, keyboard, VGA cable, scanner, printer, camera etc.)- then press the power button for at least 5 seconds, this is what we call POWER DRAIN, then try booting up your system again, if still unresolved, power off your tower, then open up your chassis, reseat the cables of your HARD DISK -- try again. if still unsolved, try entering the BIOS, check if the HARD DISK is detected..

Take out the hard drive completely and then see if you hear the clicking noise, if you do then that means the hard drive is bad. Also if it goes right to another message and you don't see the blinking cursor then that also verifies that the hard drive was bad and causing the system to hang.

Hold the power button down and let it fully power off then boot it back up. If you get a prompt saying Windows did not shut down normally, select Last Known Good Configuration.

So.. you can select safe mode? Or you turn it on and it is resuming into the blank screen?

If the latter. Unplug the power, pull the battery out for 20 seconds or so. Then put it all back together and try booting up.

Hmm... Any errors on the screen?

Could be a power supply. Fluctuations in that can cause power drops, which would be visible in the video card, and if severe enough, cause the PC to shut off. There are 4 screws and one 1 wire holding those in. It would take about 10 minutes to replace and probably cost you $40-$50 in parts.

To have Geeks do it: Probably $100.