HP Pavilion All-in-One turns on but there is no display (black screen)

[BK66]

I own a HP Pavilion All-in-One and recently upgraded it from Windows 10 to Windows 11. Previously, I had the problem where  my screen flickered randomly and I would have to adjust the power cord in order to fix the problem.

However, a couple of days my screen went black and I could not get fix the problem by adjusting the power cord. Basically, if I turn on my computer it boots up (the windows sound effect plays) but does not display anything.  

I tried the following solutions but they all did not work:

1. Hard reset

2. Recovering the bios (I get the 8 beeps but there is no display of the BIOS screen)

3. Disconnect external devices from the computer and then restarting

[BeemerBiker]

Borrow a second monitor connect it up and press the WindowsKey + P   then press  CURSOR down then ENTER

you need to select duplicate.  Use the cursor keys on the keyboard not the mouse

HDMI cable to TV set can also work

 bring up the device manager and look for problems.  

Take opportunity to copy important documents to flash drive

if in warranty you can contact support

1) Click on this link -
https://support.hp.com/us-en/contact-hp
2) Select your product type below.
3) Enter the serial of your device.
4) Select the country from the drop-down.
5) Select the chat or get phone number options based on your preferences.
6) Fill the web form and proceed further.
To obtain parts use this list:
https://parts.hp.com/hppartsIGSO/Part_Resellers.aspx?from=ERP&cc=GB〈=EN&geo_code=EMEA