HP Omen pc doesn’t boot

[SimonV3]

My HP Omen desktop pc 3y old suddenly doesn’t boot anymore.
When I power up all lights and fans work, but the monitor, mouse and keyboard are not doing anything. 
tested monitor on another pc —> monitor works fine. 

unplugged power and pressed power button 30secs —> no fix. 

reseated the ram —> no fix. 

I don’t see any error lights or hear any beeps.

I have a spare gaming pc that I can use to replace parts for troubleshooting, but don’t know what to do first, and I don’t want to mess things up further. 

[BeemerBiker]

How did this happen?

• Power surge?
• Add memory or install new device?
• Update BIOS?
• Windows update?

Any blinking lights or beeps?
Click here for AIO or desktop codes

This is how to do a hard reset

• Turn on the computer by holding the power button down for 20 full seconds then release.
• Press the Power button one more time (if necessary) to start the computer.
• Tap the ESC key about once a second after you see the LEDs on the keyboard flash.
• Press F2 to run diagnostics: (v) 2.6 or later is recommended.

Makes sure you can pass the memory and disk test. If you still cannot power up then check warranty

Let me know what you find out.

[SimonV3]

Thanks for the feedback. 
I recently did a bios update and a windows update. That was one or more days ago, and the pc booted fine this morning.
No new devices or power surge. 
Problems started when I came back to my pc and wanted to wake it. Nothing happened so I forced shut down by pressing the power button. 

I tried resetting the bios by using the jumper on cmos pins —> no fix

I tried your hard reset method while tapping escape, pc booted 3 times after I did this, but nothing happens on the monitor, and keyboard and mouse lights are still off —> no fix 

[BeemerBiker]

According to Google AI quote: " most, if not all, HP Omen motherboards will have a BIOS recovery mechanism, often implemented as a dedicated jumper or button on the board, allowing users to recover the BIOS even if it becomes corrupted; however, to confirm the exact location and functionality, you should always consult the specific motherboard manual for your particular Omen model. "



On my omen shire motherboard the jumper is numbered 5 and 6, identified as "BBR", and is adjacent to the M.2 Wi-Fi. Shorting it while powering up will flash the bios.
.