Got to ask. Have you ever build a computer before?
If the power light is green and "234" shows its: USB subsystem configuration activity in progress or USB subsystem failure.
If the power light is orange and "234" is blinking: System on. BIOS not execution. This is the transition state to POST states.
And from what I can see... its not good news.
Could be that your CPU for some reason is dead, or that your motherboard is faulty...
You could try to clear CMOS:https://www.dell.com/support/article/no/no/nobsdt1/sln284985/how-to-perform-a-bios-or-cmos-reset-and-or-clear-the-nvram-on-your-dell-system?lang=en
Besides that the next step would be to take the system 100% apart and inspect every part, and build the system back up again.
This is one of the downsides of pre-built systems... When they one day stops working... can be a pain to get them up and running again (if you can)