Greetings,
Welcome to the forum.
I am not a HP employee.
You have some type of hardware problem. I can't check your PC's date of manufacture or specifications without a product number. Hardware failure increases with the age of the PC.
Something is causing your PC to hang during the Power On Self Test phase.
It would also be good to try a different power supply, check all connections on the motherboard, and try different, known good RAM in conjunction with the following steps. Replace the CR2032 motherboard battery.
Now see if you can get the PC to display any error messages. You would have to shut down the PC and disconnect from AC power for each of the following troubleshooting steps:
Only connect a monitor to see if the PC will continue to the Windows log in screen.
Remove any add in PCI or PCIe cards if applicable. Try on board graphics if using a discrete graphics card or install a discrete graphics card if using on board graphics. I know you have video but you can't rule out any component.
Then disconnect the HDD and optical drive. Try again
Now disconnect front USB and the card reader. Try again
Then remove all RAM modules. Try again.
Then try one stick of RAM in each memory socket. Repeat this process with all sticks of RAM removed in the previous step.
You are working your way down to a failing motherboard.
Troubleshooting is a process.
Regards