Could be a corrupted BIOS.
Here are some of the symptoms you may experience after trying to restarting the HP laptop:
* Windows does not start and the caps lock or num lock keys blink, or the computer beeps 2 times
* Power light or charging light continues to blink
* A BIOS APPLICATION ERROR 501 is displayed
* The computer stops at a black or blank screen when turned on
* The computer turns on and you might hear the internal fan, but the display is blank and Windows does not start
Note: Different models may use different keystrokes.
You can try:
* Turn off the computer and be sure that the AC adapter is connected to power.
* Press and hold the Windows + b keys, and then simultaneously press the power button.
* After 2 to 3 seconds, continue to press and hold the Windows + b keys, but release the power button. You might hear a series of beeps.
** If the HP BIOS Update screen is not displayed, repeat the previous steps but press the Windows + v keys. If the screen is still not displayed, your computer might not support the feature or there is a hard drive issue.
There is also the USB drive method. Download the latest BIOS update for your HP laptop on another computer and make a bootable USB drive
[link|https://support.hp.com/us-en/document/ish_3932413-2337994-16|This HP site gives more details. Key strokes may be different for different models.|new_window=true]
Read the direction several time and make sure you follow them exactly. Timing can be very important.
***[link|https://www.youtube.com/watch?v=OkadkPyGjY4|Here is another video discussing the HP corrupt BIOS repair.|new_window=true]***
Good luck. Let us know how it goes.