PC not turning on - Loud high pitched noise

[roisin1106]

My PC will not turn on, it is connected to power and when i press the on button the led turns on for a split second, turns off then this high pitched noise emits from the fans and the screen is black. This noise does not stop until the laptop turns off after about 20 minutes. I’ve tried holding the power button for 15-30 seconds without power and then plugging back in but it does the same thing.

[VikramTheGreat]

Hi @roisin1106,

Welcome to the HP Support Community.
 

Thank you for posting your query. I will be glad to help you.

Based on your description, it seems like your HP laptop is experiencing a hardware-level fault, possibly related to the motherboard, power delivery, or internal components like the fan or CPU. The high-pitched noise and failure to boot suggest it’s not completing POST (Power-On Self-Test).
 

Here are a few steps you can try:

1. Hard Reset (again, with a twist):
   • Disconnect all external devices.
   • Unplug the power adapter and remove the battery (if removable).
   • Press and hold the power button for 60 seconds.
   • Reconnect only the power adapter and try powering on.
      
2. Check for LED Blink Codes:
   • If the power LED or Caps Lock blinks in a pattern, it could be a diagnostic code. Count the blinks and refer to HP’s LED error code guide for interpretation.
      
3. Try an External Display:
   • Connect your laptop to an external monitor to rule out a display issue.
      
4. BIOS Recovery: 
5. Shut down the computer, and keep the charger plugged in
6. Hold down the Windows and B buttons together while the computer is still turned off. 
7. Turn on the computer and continue to hold the Windows and B buttons until a BIOS Recovery screen appears. 
8. Follow the on-screen instructions and click on OK.

I hope this helps.

Take care and have a good day.

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VikramTheGreat

HP Support